China's Fu Yuanhui poses with her gold medal after winning the women's 50m backstroke final at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Hannibal Hanschke 

China's Ning Zetao celebrates after winning the men's 100m freestyle final at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Michael Dalder

China's Ning Zetao celebrates after winning the men's 100m freestyle final at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Michael Dalder

China's Ning Zetao celebrates after winning the men's 100m freestyle final at the Aquatics World Championships in Kazan, Russia, August 6, 2015. REUTERS/Michael Dalder

Paddles belonging to Britain's rowing team is pictured next to athletes' footwear at the deck during a training session at the World Rowing Junior Championships in Rodrigo de Freitas Lagoon in Rio de Janeiro, Brazil August 5, 2015. The World Rowing Junior Championships event is a test event for the Rio 2016 Olympic Games. Rio de Janeiro started the one year countdown to host the Rio 2016 Olympic Games today. REUTERS/Ricardo Moraes 

Daiya Seto of Japan reacts after the men's 200m butterfly heats at the Aquatics World Championships in Kazan, Russia August 4, 2015. REUTERS/Michael Dalder

A spectator in fancy dress watches the morning swimming heats during the Aquatics World Championships in Kazan, Russia August 3, 2015. REUTERS/Stefan Wermuth

Robert Tackman (front), mayor of East Syracuse, NY, swims with others in Onondaga Lake, near Liverpool, New York July 22, 2015. A group of swimmers took a plunge in a New York lake long considered one of the most polluted U.S. waterways to prove it is now safe for recreation. About 40 swimmers participated in the symbolic swim on Wednesday in Onondaga Lake, northwest of Syracuse, the first time since 1940 that people have been allowed in the water. REUTERS/Matthew Liptak 

Mick Fanning of Australia, who survived a shark attack, reacts during a media conference in Sydney, Australia July 21, 2015. A visibly shaken Fanning arrived home in Australia on Tuesday saying he would not turn his back on surfing despite needing a "miracle" to survive a shark attack off the coast of South Africa at the weekend. The three-times world champion was paddling out to ride his first wave in the final of the World Surf League's J-Bay Open on Sunday when an unidentified species of shark knocked him off his board. REUTERS/David Gray 

Mick Fanning of Australia, who survived a shark attack, reacts during a media conference in Sydney, Australia July 21, 2015. A visibly shaken Fanning arrived home in Australia on Tuesday saying he would not turn his back on surfing despite needing a "miracle" to survive a shark attack off the coast of South Africa at the weekend. The three-times world champion was paddling out to ride his first wave in the final of the World Surf League's J-Bay Open on Sunday when an unidentified species of shark knocked him off his board. REUTERS/David Gray TPX IMAGES OF THE DAY

Mick Fanning (R) of Australia and fellow surfer and compatriat Julian Wilson react during a news conference in Sydney, Australia July 21, 2015, after Fanning was attacked by a shark during the finals on Sunday of the J-Bay Open in Jeffrey's Bay, South Africa. REUTERS/David Gray 

Mick Fanning of Australia speaks during a news conference in Sydney, Australia July 21, 2015, after he was attacked by a shark during the finals of the J-Bay Open on Sunday in Jeffrey's Bay, South Africa. REUTERS/David Gray 

Mick Fanning of Australia reacts during a news conference in Sydney, Australia July 21, 2015, after he was attacked by a shark during the finals of the J-Bay Open on Sunday in Jeffrey's Bay, South Africa. REUTERS/David Gray 

Mick Fanning of Australia reacts during a news conference in Sydney, Australia July 21, 2015, after he was attacked by a shark during the finals of the J-Bay Open on Sunday in Jeffrey's Bay, South Africa. REUTERS/David Gray 

Mick Fanning of Australia reacts during a news conference in Sydney, Australia July 21, 2015, after he was attacked by a shark during the finals of the J-Bay Open on Sunday in Jeffrey's Bay, South Africa. REUTERS/David Gray 

Reed Platenious holds surfer Ben Murphy's board during the Canadian Surf Championship in Tofino, British Columbia May 31, 2015. REUTERS/Kevin Light TPX IMAGES OF THE DAY

Three synchronized swimmers wear hats made out of 800 chrysanthemums each at the M & G Retreat garden at the Royal Horticultural Soceity's Chelsea Flower Show in London, Britain, May 18, 2015. REUTERS/Toby Melville TPX IMAGES OF THE DAY

Three women swim in the M & G Retreat garden whilst wearing hats made out of 800 chrysanthemums each at the Royal Horticultural Soceity's Chelsea Flower Show in London, Britain, May 18, 2015. REUTERS/Toby Melville

A member of the Oxford Men's Rowing team throws a wellington boot to shore as they take part in a training session on the Thames river in London April 6, 2015. REUTERS/Neil Hall TPX IMAGES OF THE DAY 

Vickie Leuenberger (L) practices with a mermaid tail with AquaMermaid founder Marielle Chartier Henault in a pool in Montreal, February 19, 2015. In addition to mermaid-themed parties the school offers a variety of fitness classes. Picture taken February 19, 2015. REUTERS/Christinne Muschi (CANADA - Tags: SOCIETY SPORT SWIMMING) 

Divers prepare their gear on the deck of the Search and Rescue (SAR) ship KN Purworejo during a search operation for passengers onboard AirAsia Flight QZ8501 in the Java Sea January 4, 2015. Bad weather forced divers trying to identify sunken wreckage from the crashed AirAsia passenger jet to abort their mission on Sunday and Indonesian officials said they had not yet picked up any signals from the lost plane's "black box". The Airbus A320-200 crashed into the Java Sea about 40 minutes after taking off last Sunday from Indonesia's second-largest city Surabaya en route for Singapore. There were no survivors. REUTERS/Beawiharta (INDONESIA - Tags: DISASTER MARITIME TRANSPORT) 

An elderly Vietnamese man smiles while rowing his boat on a river in the ancient city of Hoi An, Quang Nam province, November 20, 2014.
REUTERS/Stefano Rellandini (VIETNAM - Tags: SOCIETY) 

Vienna Werner, 16, rides a wave dressed as a rabbit during the 7th annual ZJ Boarding House Haunted Heats Halloween surf contest in Santa Monica, California October 25, 2014. REUTERS/Lucy Nicholson (UNITED STATES - Tags: SPORT SOCIETY) 

Bronze medallist Yasuhiro Koseki of Japan competes in the Men's 200m Breaststroke final at the Munhak Park Tae-hwan Aquatics Center during the 17th Asian Games in Incheon September 23, 2014. REUTERS/Tim Wimborne (SOUTH KOREA - Tags: SPORT SWIMMING) 

A finished diving helmet built by artisan Nicholas Toth sits in the wood-frame shop next to the Anticlote River in Tarpon Springs, Florida, April 6, 2014. Toth is among the last to carry on the century-old family skill of hand crafting helmets for sponge divers. Though rarely worn nowadays, Toth's helmets sell for more than $20,000. Picture taken April 6, 2014. REUTERS/Steve Nesius (UNITED STATES - Tags: SOCIETY) 

A diver from a bomb-disposal unit holds an unexploded shell recovered in a river in Cappy, close to WWI battlefields, March 19, 2014. Every year the bomb-disposal unit from Amiens removes several tonnes of shells, shrapnel, gas shells, unexploded grenades, called "engins de mort" (weapons of death), from surrounding fields and rivers. The year 2014 marks the 100th anniversary of the start of the First World War. Picture taken March 19, 2014. REUTERS/Pascal Rossignol (FRANCE - Tags: MILITARY ANNIVERSARY SOCIETY) 

A woman paddles her kayak on the Lac de Joux on a sunny morning in Le Pont April 9, 2014. REUTERS/Denis Balibouse (SWITZERLAND - Tags: ENVIRONMENT TRAVEL TPX IMAGES OF THE DAY) 

Prince Albert II of Monaco (C) and his wife Princess Charlene (L) wave to the children as they arrive for the traditional Christmas tree ceremony at the Monaco Palace as part of Christmas holiday season in Monaco December 18, 2013. REUTERS/Eric Gaillard (MONACO - Tags: ENTERTAINMENT ROYALS) 

A participant dressed as Captain America surfs during the third annual Rockaway Halloween surf competition at Rockaway Beach in the Queens borough of New York November 2, 2013. REUTERS/Eric Thayer (UNITED STATES - Tags: SOCIETY) 

Participants prepare before the third annual Rockaway Halloween surf competition at Rockaway Beach in the Queens borough of New York November 2, 2013. REUTERS/Eric Thayer (UNITED STATES - Tags: SOCIETY TPX IMAGES OF THE DAY) 

Competitors line up to surf in the ZJ Boarding House Halloween Surf Contest in Santa Monica, California October 26, 2013. REUTERS/Lucy Nicholson (UNITED STATES - Tags: SPORT SOCIETY) 

Sean Owolo, 40, (R) dressed as the Grim Reaper, and Marius Petrulis, 36, dressed as a chicken, prepare to compete in the ZJ Boarding House Halloween Surf Contest in Santa Monica, California October 26, 2013. REUTERS/Lucy Nicholson (UNITED STATES - Tags: TPX IMAGES OF THE DAY SPORT SOCIETY) 

Members of the Shembe Church pray while kneeling in water on the Durban beach front, October 5, 2013. REUTERS/Rogan Ward (SOUTH AFRICA - Tags: RELIGION SOCIETY TPX IMAGES OF THE DAY) 

Synchronized swimmers present creations from the Adidas by Stella McCartney Spring/Summer 2014 collection during London Fashion Week September 17, 2013. REUTERS/Suzanne Plunkett (BRITAIN - Tags: FASHION SPORT TPX IMAGES OF THE DAY) 

Spectators look at some two thousand swimmers as they take off from the Maritime museum for the second Amsterdam City Swim in Amsterdam September 8, 2013. The Amsterdam City Swim is held to raise money for research into Amyotrophic lateral sclerosis (ALS). The participants swam a total of 2013 meters in the canals of Amsterdam. REUTERS/Cris Toala Olivares (NETHERLANDS - Tags: SPORT SWIMMING SOCIETY) 

Prince Albert II of Monaco hugs his wife Princess Charlene of Monaco after he and his team won the Pro AM finale of the Masters petanque tournament in Monaco September 5, 2013. REUTERS/Eric Gaillard (MONACO - Tags: ENTERTAINMENT ROYALS) 

A combination photo shows Princess Charlene of Monaco walking on the beach during a swimming event for her foundation in Capbreton, Southwestern France, September 1, 2013. REUTERS/Regis Duvignau (FRANCE - Tags: ROYALS ENTERTAINMENT) 

Princess Charlene of Monaco walks on the beach during a swimming event for her foundation in Capbreton, Southwestern France, September 1, 2013. REUTERS/Regis Duvignau (FRANCE - Tags: ROYALS ENTERTAINMENT) 

A Palestinian couple from Ramallah walk next to an Israeli surfer near the shore of the Mediterranean sea at a beach in Tel Aviv during Eid al-Fitr, which marks the end of the holy month of Ramadan August 11, 2013. The Israeli Coordinator for Government Activities in the Territories' (COGAT) responsible for implementing Israel's civilian policy in the occupied West Bank and Gaza Strip, eased permit restrictions for thousands of Palestinians wanting to enter Israel following a security assessment, allowing many to enjoy the beaches along Israel's Mediterranean shoreline during the Eid al-Fitr holiday. REUTERS/ Nir Elias (ISRAEL - Tags: POLITICS RELIGION SOCIETY TPX IMAGES OF THE DAY) 

Sweden's Sarah Sjostrom celebrates after winning the women's 100m butterfly final during the World Swimming Championships at the Sant Jordi arena in Barcelona July 29, 2013. REUTERS/Michael Dalder (SPAIN - Tags: SPORT SWIMMING TPX IMAGES OF THE DAY)

A diver holds his mask on a small boat on Yangon River after searching for coal and iron from sunken ships July 10, 2013. Every morning and evening during high tide, up to 40 boats of different shapes and sizes with crews of between four and eight people leave the former capital for the dangerous job of salvaging items from Yangon River's muddy waters. Wearing flimsy-looking gas masks attached to rubber water pipe, the divers jump into the water in search of coal and iron from sunken ships to be sold later. Some divers have lost their lives on the job when their ropes break or when they get caught in fishing nets and hooks. Divers say each boat earns about $1000 a month in this tiring and lethal job. Picture taken July 10, 2013. REUTERS/Damir Sagolj (MYANMAR - Tags: SOCIETY BUSINESS EMPLOYMENT TPX IMAGES OF THE DAY TRANSPORT) 

A diver adjusts his mask on a small boat on Yangon river as he prepares to search for coal and iron from sunken ships, July 10, 2013. Every morning and evening during high tide, up to 40 boats of different shapes and sizes with crews of between four and eight people leave the former capital for the dangerous job of salvaging items from Yangon River's muddy waters. Wearing flimsy-looking gas masks attached to rubber water pipe, the divers jump into the water in search of coal and iron from sunken ships to be sold later. Some divers have lost their lives on the job when their ropes break or when they get caught in fishing nets and hooks. Divers say each boat earns about $1000 a month in this tiring and lethal job. Picture taken July 10, 2013. REUTERS/Damir Sagolj (MYANMAR - Tags: SOCIETY BUSINESS EMPLOYMENT TRANSPORT) 

Mexican sewer diver Julio Cu Camara, 52, kneels in a cage while putting on his helmet before a dive at the city's drainage system plant in Mexico City March 21, 2013. Cu Camara's job involves diving in the city's sewage system to clear blockages and repair infrastructure, on an average of four times a month, for about 30 minutes to six hours depending on the amount of work needed. Cu Camara, who started working as a sewer diver 30 years ago, uses a diving suit and helmet that weigh more than 40 kg to protect him during his dives. During his working experience, he has found dead humans, horses, weapons and car parts among other things. Mexico City has a drainage system which measures more than 7,456 miles (12,014 km) long. REUTERS/Edgard Garrido (MEXICO - Tags: SOCIETY ENVIRONMENT BUSINESS EMPLOYMENT TPX IMAGES OF THE DAY) 

Inge Natoli, 90, (R) who emigrated to Michigan from Germany and has lived in Sun City for 29 years practices synchronized swimming with Barbara Miller, 77, in Sun City, Arizona, January 9, 2013. Sun City was built in 1959 by entrepreneur Del Webb as America’s first active retirement community for the over-55's. Del Webb predicted that retirees would flock to a community where they were given more than just a house with a rocking chair in which to sit and wait to die. Today’s residents keep their minds and bodies active by socializing at over 120 clubs with activities such as square dancing, ceramics, roller skating, computers, cheerleading, racquetball and yoga. There are 38,500 residents in the community with an average age 72.4 years. Picture taken January 9, 2013. REUTERS/Lucy Nicholson (UNITED STATES - Tags: SOCIETY)

ATTENTION EDITORS - PICTURE 3 OF 30 FOR PACKAGE 'THE SPORTY SENIORS OF SUN CITY'
SEARCH 'SUN CITY' FOR ALL IMAGES 

Competitors prepare to get into the water during the UK Cold Water Swimming Championships at Tooting Bec Lido in south London January 26, 2013. REUTERS/Luke MacGregor (BRITAIN - Tags: SPORT SOCIETY) 

Swimmers prepare to get into the water during the UK Cold Water Swimming Championships at Tooting Bec Lido in south London January 26, 2013. REUTERS/Luke MacGregor (BRITAIN - Tags: SPORT SOCIETY TPX IMAGES OF THE DAY) 

Prince Albert II of Monaco exchanges gifts with Pope Benedict XVI (C) next to his wife Princess Charlene (R) during a private audience at the Vatican January 12, 2013. REUTERS/Vincenzo Pinto/Pool (VATICAN - Tags: RELIGION ROYALS ENTERTAINMENT) 

A diver dressed in a Santa Claus costume gestures as children watch during a promotional event for the Christmas "Sardines Feeding Show with Santa Claus" at the Coex Aquarium in Seoul December 11, 2012. REUTERS/Kim Hong-Ji (SOUTH KOREA - Tags: SOCIETY MARITIME ANIMALS) 

Valery Shevchenko, 40, dressed as Santa Claus, ice sails on the frozen Bolshoye lake near the village of Parnaya, about 340 km (211 miles) southwest of Russia's Siberian city of Krasnoyarsk, December 2, 2012. Picture taken December 2, 2012. REUTERS/Ilya Naymushin (RUSSIA - Tags: SOCIETY ENVIRONMENT SPORT) 

A diver dressed as Santa Claus swims with a dolphin at Hakkeijima Sea Paradise in Yokohama, south of Tokyo November 27, 2012. The underwater feeding session involving divers dressed as Santa will take place every day until Christmas Day. REUTERS/Yuriko Nakao (JAPAN - Tags: SOCIETY ANIMALS TPX IMAGES OF THE DAY) 

A man dressed as a friar jumps from a 13-meter high cliff during the "Jump of the Friar", along Herradura Beach in Lima, November 16, 2012. The jump was to commemorate a local legend, that of a friar who leapt into the sea from the same rock to commit suicide over his love of a woman, some two hundred years ago. REUTERS/Mariana Bazo(PERU - Tags: SOCIETY TPX IMAGES OF THE DAY) 

A man surfs on his back dressed as a skeleton during the ZJ Boarding House Halloween surf contest in Santa Monica, October 27, 2012. REUTERS/Lucy Nicholson (UNITED STATES - Tags: SPORT SOCIETY) 

West Highland Terrier 'Surf Dog Joey' competes on a board with three sharks in the Surf City Surf Dog contest in Huntington Beach September 30, 2012. REUTERS/Lucy Nicholson (UNITED STATES - Tags: SOCIETY ANIMALS) 

Ten-year-old Lucas Amorim, who has phocomelia, affecting the growth of his arms, swims during a training session in Manaus, Amazonas State, September 19, 2012. Lucas, who was motivated to become a swimmer two years ago by a cousin who is also handicapped and swims competitively, recently won the Amazonas State championship in the S5 category of 50m freestyle for his age group. Apart from his dreams of representing Brazil in a future Paralympics, Lucas wants to be a civil engineer some day. Picture taken September 19, 2012. REUTERS/Bruno Kelly (BRAZIL - Tags: SPORT SWIMMING SOCIETY TPX IMAGES OF THE DAY) 

Water polo players warm up before their training in a public swimming pool in Sao Paulo September 18, 2012. The temperature reached almost 35 degrees Celsius (95 degrees Fahrenheit) on Tuesday, during the last week of winter in Brazil. REUTERS/Paulo Whitaker (BRAZIL - Tags: SPORT WATER POLO ENVIRONMENT) 

Ireland's James Scully puts on goggles before diving into the pool for a training session at the London 2012 Paralympic Games in the Aquatics Centre September 8, 2012. REUTERS/Suzanne Plunkett (BRITAIN - Tags: SPORT OLYMPICS SWIMMING TPX IMAGES OF THE DAY) 

China's Xu Qing (L), Zheng Tao (C) and Brazil's Adriano de Lima prepare to race in the men's 50m Freestyle - S6 heats during the London 2012 Paralympic Games at the Aquatics Centre in the Olympic Park September 4, 2012. The S6 category is for swimmers who have amputations of both arms, swimmers of short stature or moderate co-ordination problems.

REUTERS/Luke MacGregor (BRITAIN - Tags: SPORT OLYMPICS SWIMMING)