The Wildstrubel mountain and the Plaine Morte glacier are pictured, days ahead federal elections, in Lenk, Switzerland October 14, 2019. Picture taken October 14, 2019. REUTERS/Denis Balibouse

The moon rises over Stoneham, Colorado, U.S. October 12, 2019. REUTERS/Jim Urquhart

Fresh shoe prints are seen at a migrant crossing spot on the Rio Grande near Mission, Texas, U.S., July 25, 2019. Picture taken July 25, 2019. REUTERS/Loren Elliott

A white stork flies off a nest in front of a church's cross in Rust, Austria, April 16, 2019. REUTERS/Lisi Niesner

White storks are seen inside their nest on a chimney above the rooftops in Rust, Austria, April 16, 2019. REUTERS/Lisi Niesner

White storks are seen inside their nest on a chimney above the rooftops in Rust, Austria, April 16, 2019. REUTERS/Lisi Niesner

White storks are seen inside their nest on a chimney above the rooftops in Rust, Austria, April 16, 2019. REUTERS/Lisi Niesner

People belonging to a caravan of migrants from Honduras en route to the United States, sleep at the Central Park of Tapachula, Mexico, April 13, 2019. REUTERS/Jose Cabezas

A migrant, part of a caravan of thousands from Central America trying to reach the United States, stands in a shelter in Tijuana, Mexico, November 19, 2018. REUTERS/Hannah McKay TPX IMAGES OF THE DAY

A migrant, part of a caravan of thousands from Central America trying to reach the United States, climbs the border fence between Mexico and the United States, in Tijuana, Mexico, November 18, 2018. REUTERS/Hannah McKay TPX IMAGES OF THE DAY

A migrant, part of a caravan of thousands from Central America trying to reach the United States, climbs the border fence between Mexico and the United States, in Tijuana, Mexico, November 18, 2018. REUTERS/Hannah McKay

The hand of a U.S. Marine is shown as he helps install concertina wire at the U.S. Mexico border in preparation for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

Concertina wire installed by U.S. Marines is shown along U.S. Mexico border in preparation for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

Concertina wire is shown where vehicles enter the United States from Mexico as authorities prepare for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

Concertina wire installed by U.S. Marines is shown along U.S. Mexico border in preparation for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

Concertina wire is shown as vehicles enter the United States from Mexico as authorities prepare for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

Concertina wire installed by U.S. Marines is shown along U.S. Mexico border in preparation for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

Concertina wire installed by U.S. Marines is shown along U.S. Mexico border in preparation for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

The hand of a U.S. Marine is shown as he helps install concertina wire at the U.S. Mexico border in preparation for the arrival of a caravan of migrants at the San Ysidro border crossing in San Diego, California, U.S. November 15, 2018. REUTERS/Mike Blake

A migrant man, part of a caravan of thousands traveling from Central America en route to the United States, receives vaccination for influenza A H1N1 in a makeshift camp in Mexico City, Mexico, November 15, 2018. REUTERS/Ueslei Marcelino

A migrant, part of a caravan of thousands traveling from Central America en route to the United States, looks out to the city through a wall from inside a makeshift camp in Mexico City, Mexico, November 7, 2018. REUTERS/Hannah McKay TPX IMAGES OF THE DAY

Migrants from Honduras, part of a caravan en route to the United States, eat a meal as they wait to reunite with more migrant, in Tecun Uman, Guatemala October 25, 2018. REUTERS/Carlos Garcia Rawlins

Laundry belonging to Congolese migrants expelled from Angola who crossed the border is aired to dry near Kamako, Kasai province near the border with Angola, in the Democratic Republic of the Congo, October 13, 2018. Picture taken October 13, 2018. REUTERS/Giulia Paravicini

Central American migrants cross the Suchiate river into Mexico on a raft as they try to reach a migrant caravan heading to U.S., in Ciudad Hidalgo, Mexico October 23, 2018. REUTERS/Ueslei Marcelino TPX IMAGES OF THE DAY

Central American migrants cross the Suchiate river into Mexico on a raft as they try to reach a migrant caravan heading to U.S., in Ciudad Hidalgo, Mexico October 23, 2018. REUTERS/Ueslei Marcelino

Undocumented Venezuelan migrants walk along the road between Berlin and Bucaramanga, near La Corcova, Colombia August 27, 2018. The migrants often walk in pitch darkness along dangerous mountain roads while trucks speed by. REUTERS/Carlos Garcia Rawlins SEARCH "MIGRANT TACHIRA" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. TPX IMAGES OF THE DAY TPX IMAGES OF THE DAY

Geese fly near the village of Myshanka, Belarus October 6, 2018. Picture taken October 6, 2018. REUTERS/Vasily Fedosenko

General view of Kani Plave village near Dhiha village in Duhok, Iraq September 11, 2018. Picture taken September 11, 2018. REUTERS/Ari Jalal

Shoes are displayed outside a hut as its inhabitants prepare to move out of the Roma shanty town of El Gallinero, on the outskirts of Madrid, Spain, September 25, 2018. REUTERS/Susana Vera SEARCH "VERA EL GALLINERO" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Shoes are displayed outside a hut as its inhabitants prepare to move out of the Roma shanty town of El Gallinero, on the outskirts of Madrid, Spain, September 25, 2018. REUTERS/Susana Vera SEARCH "VERA EL GALLINERO" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

A man puts out a bonfire before leaving the Roma shanty town of El Gallinero, on the outskirts of Madrid, Spain, September 27, 2018. REUTERS/Susana Vera SEARCH "VERA EL GALLINERO" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

A drawing of a house hangs on the wall of an empty hut after its inhabitants left the Roma shanty town of El Gallinero, on the outskirts of Madrid, Spain, September 25, 2018. REUTERS/Susana Vera SEARCH "VERA EL GALLINERO" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Slums are seen in front of the luxury apartments in Colombo, Sri Lanka September 28, 2018. REUTERS/Dinuka Liyanawatte

A residential area is seen in Colombo, Sri Lanka September 28, 2018. REUTERS/Dinuka Liyanawatte

Street lights are seen at night in the village of Gurgurnica, Macedonia July 2, 2018. Picture taken July 2, 2018. REUTERS/Ognen Teofilovski

A general view of Gurgurnica village, Macedonia July 2, 2018. Picture taken July 2, 2018. REUTERS/Ognen Teofilovski

Residential houses are seen in Dal Lake in Srinagar, India September 26, 2018. REUTERS/Danish Ismail

Houses at the Santo Amaro slum are seen with the Sugar Loaf mountain in the background in Rio de Janeiro, Brazil September 24, 2018. REUTERS/Pilar Olivares TPX IMAGES OF THE DAY

Houses at the Santo Amaro slum are seen in Rio de Janeiro, Brazil September 24, 2018. REUTERS/Pilar Olivares

Houses at the Santo Amaro slum are seen with the Sugar Loaf mountain in the background in Rio de Janeiro, Brazil September 24, 2018. REUTERS/Pilar Olivares

An aerial view of Hla Phoe Khaung transit camp for Rohingya who decide to return back from Bangladesh, is seen in Maungdaw, Rakhine state, Myanmar, September 20, 2018. Ye Aung Thu/Pool via REUTERS TPX IMAGES OF THE DAY

Thousands of wading birds including Oystercatchers fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville TPX IMAGES OF THE DAY

A flock of geese are seen flying as thousands of wading birds move between the sea and dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Thousands of wading birds, including Knot and Godwit, move onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Thousands of wading birds, including Knot, fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Thousands of wading birds, including Knot and Godwit, move onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

A murmuration is seen above a trawler as thousands of wading birds fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Murmurations are seen above a boat as thousands of wading birds fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Murmurations are seen above a boat as thousands of wading birds fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Thousands of wading birds, including Oystercatcher, fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Thousands of wading birds, including Knot, fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Thousands of wading birds including Oystercatchers fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Birdwatchers view from a hide as thousands of wading birds fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

Thousands of wading birds fly onto dry sandbanks during the month's highest tides at The Wash estuary, near Snettisham in Norfolk, Britain, September 13, 2018. REUTERS/Toby Melville

A general view of the refugee camp near Atimah village, Idlib province, Syria September 11 ,2018. REUTERS/Khalil Ashawi

German customs officers walk through Cologne's main railways station during a raid looking for illegal workers in restaurants, at constructions sites and in the logistics sector in Cologne, Germany September 11, 2018. REUTERS/Wolfgang Rattay

A general view shows the main part of the Palestinian Bedouin encampment of Khan al-Ahmar in the occupied West Bank September 5, 2018. REUTERS/Mohamad Torokman

A view of Punaca on the shores of the dried lake Poopo affected by climate change, in the Oruro Department, Bolivia, May 4, 2018. Picture taken May 4, 2018. REUTERS/David Mercado

An Urus Muratos woman is seen in Punaca on the shores of the dried lake Poopo affected by climate change, in the Oruro Department, Bolivia, December 16, 2017. Picture taken December 16, 2017. REUTERS/David Mercado

The sun sets over a sheep herd in Darkhan-Uul province, Mongolia, August 13, 2018. Picture taken August 13, 2018. REUTERS/B. Rentsendorj