U.S. President Barack Obama stops in front of the Treasury as he takes a walking tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS TRAVEL) 

A U.S. Secret Service helicopter flies over the ancient historic and archaeological site of Petra before a visit by U.S. President Barack Obama March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS MILITARY TRAVEL) 

U.S. President Barack Obama (2nd R) makes a stop at "The Treasury" during a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (R) greets a Bedouins guard during a stop at "The Treasury", while on a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

Members of the U.S. Secret Service Counter Assault Team survey a path after U.S. President Barack Obama walked through it during his tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL MILITARY) 

U.S. President Barack Obama (C) stops to look at "The Treasury" during a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (2nd R) makes a stop at "The Treasury" during a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (L) stops to look at "The Treasury" during a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (2nd R) tours the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama takes a walking tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama gestures during a walking tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (R) poses at the Treasury as he takes a walking tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Muhammad Hamed (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (2nd R) stops to look at the Treasury while he receives a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (L) stops to look at the Treasury while he receives a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (L) stops to look at the Treasury while he receives a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama (C) stops to look at the Treasury while he receives a tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS TRAVEL) 

Members of the U.S. Secret Service Counter Assault Team survey a path before U.S. President Barack Obama walks through it during his tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS MILITARY TRAVEL) 

U.S. President Barack Obama stops to look at the Treasury as he takes a walking tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama stops to look at the Treasury as he takes a walking tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS TRAVEL) 

U.S. President Barack Obama stops to look at the Treasury as he takes a walking tour of the ancient historic and archaeological site of Petra March 23, 2013. Obama visited Jordan's ancient city of Petra on Saturday as he wrapped up a four-day Middle East tour by setting aside weighty diplomatic matters and playing tourist for a day. REUTERS/Larry Downing (JORDAN - Tags: POLITICS TRAVEL TPX IMAGES OF THE DAY) 

A tourist boy takes a picture of a camel at the Red Rose ancient city of Petra, southern Jordan, April 3, 2012. REUTERS/Ali Jarekji (JORDAN - Tags: POLITICS) 

A tourist visits the Red Rose ancient city of Petra, southern Jordan, April 3, 2012. REUTERS/Ali Jarekji (JORDAN - Tags: TRAVEL SOCIETY) 

A Bedouin woman sells souvenirs in the ruins of the ancient city of Petra April 7, 2008. Petra in Jordan was named among the modern day seven wonders of the world chosen in a poll of 100 million online voters. REUTERS/Erik de Castro (JORDAN) 

A child walks in the amphitheatre which was first constructed by the Nabataeans in the early 1st century AD and refurbished by the Romans soon after their conquest in 106 AD, in the ancient city of Petra April 7, 2008. Petra in Jordan was named among the modern day seven wonders of the world chosen in a poll of 100 million online voters. REUTERS/Erik de Castro (JORDAN) 

A policeman from the Jordanian Desert Patrol stands at the entrance of Al Khazneh (Treasury) in the ancient city of Petra April 7, 2008. The Treasury is Petra's most famous monument whose name reflects the local legend that the urn on top of the monument held the pharaoh's treasure. Petra in Jordan was named among the modern day seven wonders of the world chosen in a poll of 100 million online voters. REUTERS/Erik de Castro (JORDAN) 

A view of the ancient city of Petra January 4, 2008. REUTERS/Muhammad Hamed (JORDAN) 

A view of the ancient city of Petra January 4, 2008. REUTERS/Muhammad Hamed (JORDAN) 

Jordanian Bedouin men ride their camels in the ancient city of Petra January 4, 2008. REUTERS/Muhammad Hamed (JORDAN) 

A Jordanian Bedouin boy rides his donkey in the ancient city of Petra January 4, 2008. REUTERS/Muhammad Hamed (JORDAN) 

U.S. first lady Laura Bush (L) visits the ancient city of Petra October 26, 2007. The first lady's visit to Jordan is part of a regional tour that aims to highlight the need for countries to share their resources and unite in the fight against breast cancer. REUTERS/ Muhammad Hamed (JORDAN) 

A view of the 7,000-seat theatre (centre), which was first constructed by the Nabataeans in the early 1st centry AD and refurbished by the Romans soon after their conquest in 106 AD, in the ancient city of Petra August 30, 2007. Petra in Jordan was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 30, 2007. REUTERS/Steve Crisp (JORDAN) 

Bedouin children play in front of ad Dayr (The Monastery) in the ancient city of Petra August 31, 2007. Ad Dayr has the largest facade (45 by 50 metres/130 by 164 ft) in Petra, Jordan. Petra was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 31, 2007. REUTERS/Steve Crisp (JORDAN) 

Ahmed Ali, aged 25, a Bedouin guide sits in front of the ancient city of Petra August 31, 2007. Ad Dayr has the largest facade (45 by 50 metres/130 by 164 ft) in Petra, Jordan. Petra was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 31, 2007. REUTERS/Steve Crisp (JORDAN) 

Part of the multi-patterned, richly coloured sandstone rocks of the ancient city of Petra is portrayed in this picture taken August 29, 2007. Petra in Jordan was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 29, 2007. REUTERS/Steve Crisp (JORDAN) 

The Jordanian flag flutters in front of the Al Khazneh (Treasury) in the ancient city of Petra August 29, 2007. The Treasury is Petra's most famous monument, whose name reflects the local legend that the urn on top of the monument held the Pharaoh's treasure. Petra in Jordan was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 29, 2007. REUTERS/Steve Crisp (JORDAN) 

Ahmed Ali, aged 25, a Bedouin guide stands in front of the Roman Soldier Tomb in the ancient city of Petra, August 30, 2007. Three statues in Roman military dress are carved into the niches of the tomb facade. Petra in Jordan was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 30, 2007. REUTERS/Steve Crisp (JORDAN) 

A view of the Al Khazneh (Treasury) in the ancient city of Petra, August 30, 2007. The Treasury is Petra's most famous monument whose name reflects the local legend that the urn on top of the monument held the pharaoh's treasure. Petra in Jordan was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 30, 2007. REUTERS/Steve Crisp (JORDAN) 

A tourist takes photos from inside the al Khazneh (Treasury), situated at the end of the Siq (centre, rear), in the ancient city of Petra August 29, 2007. The Treasury is Petra's most famous monument, whose name reflects the local legend that the urn on top of the monument held the pharaoh's treasure. Petra in Jordan was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 29, 2007. REUTERS/Steve Crisp (JORDAN) 

Two women make their way along the 1.2 km-long passageway known as the Siq in the ancient city of Petra August 29, 2007. The Siq is a single block of sandstone rock that was rent apart by tectonic forces. Petra in Jordan was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 29, 2007. REUTERS/Steve Crisp (JORDAN) 

A horse-drawn carriage travels through the 1.2 km-long passageway known as the Siq in the ancient city of Petra August 29, 2007. The Siq is a single block of sandstone rock that was rent apart by tectonic forces. Petra in Jordan was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 29, 2007. REUTERS/Steve Crisp (JORDAN) 

Salem Hammed, 23, a Bedouin guide poses at the edge of the urn at the peak of ad Dayr (The Monastery) in the ancient city of Petra August 31, 2007. Ad Dayr has the largest facade (45 by 50 metres, or 130 by 164 ft) in Petra, Jordan. Petra was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 31, 2007. REUTERS/Steve Crisp (JORDAN) 

Salem Hammed, 23, a Bedouin guide, climbs to the top of ad Dayr (The Monastery) in the ancient city of Petra August 31, 2007. Ad Dayr has the largest facade (45 by 50 metres, or 130 by 164 ft) in Petra, Jordan. Petra was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 31, 2007. REUTERS/Steve Crisp (JORDAN) 

Salem Hammed, 23, a Bedouin guide stands on top of the urn at the peak of ad Dayr (The Monastery) in the ancient city of Petra August 31, 2007. Ad Dayr has the largest facade (45 by 50 metres, or 130 by 164 ft) in Petra, Jordan. Petra was recently named among the modern-day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 31, 2007. REUTERS/Steve Crisp (JORDAN) 

A camel takes a drink of water from a plastic bottle at the ancient city of Petra August 31, 2007. Petra in Jordan was recently named among the modern day seven wonders of the world chosen in a poll of 100 million online voters. Picture taken August 31, 2007. REUTERS/Steve Crisp (JORDAN) 

A girl sells postcards to tourists in Petra July 10, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. Picture taken July 10, 2007. REUTERS/May Naji (JORDAN) 

A view of the ancient tombs of Petra is seen through a hole in Jordan July 10, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. Picture taken July 10, 2007. REUTERS/May Naji (JORDAN) 

Tourists walk on the narrow road of Wadi Siq leading towards the Treasury tomb of Petra July 10, 2007.The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. Picture taken July 10, 2007. REUTERS/May Naji (JORDAN) 

A Jordanian man rides his cart in front of Obelisk Tomb in Petra July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad Hamed (JORDAN) 

Tourists walk front of Obelisk Tomb in Petra July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad Hamed (JORDAN) 

A Jordanian woman shows souvenirs to a tourist in front of the archaeological court building in Petra July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad Hamed (JORDAN) FOR BEST QUALITY IMAGE: ALSO SEE GF2E54K0V6901 

A tourist rides a donkey during a tour in Petra July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad Hamed (JORDAN) 

Australian tourists look at the Petra mountains in front of the archaeological court building in Petra July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad hamed (JORDAN) 

An Australian tourist takes pictures of the archaeological court building in Petra July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad Hamed (JORDAN)
FOR BEST QUALITY IMAGE ALSO SEE: GM1E57U197R01 

Tourists visit the Petra in front of the treasury site July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad hamed (JORDAN) 

Tourists visit the Petra in front of the treasury site July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad hamed (JORDAN) 

Tourists visit the Petra in front of the treasury site July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad Hamed (JORDAN) FOR BEST QUALITY IMAGE: ALSO SEE GF2E54L0ZA101 

Israeli Arab tourists sit in front of the treasury site in Petra July 9, 2007. The Great Wall of China, Petra in Jordan and Brazil's statue of Christ the Redeemer are among the modern day seven wonders of the world chosen in a poll of 100 million online voters, organisers said on July 7, 2007. The other four are Peru's Machu Picchu, the mountain settlement that symbolises the Inca empire, Mexico's Mayan ruins at Chichen Itza, the Colosseum in Rome and the Taj Mahal in India. REUTERS/Muhammad hamed (JORDAN)