Participants of the 77th edition of the annual Christmas swimming 'Coupe de Noel' jump into the waters of Lake Geneva, in Geneva, Switzerland, 20 December 2015. More than 1,540 men and women braved the water temperature of just 8 degrees Celsius as they swam a 120 meters distance at the traditional Christmas swimming in Geneva. (Photo by Salvatore Di Nolfi/EPA)

A man jokingly poses with a new installation of British graffiti artist Banksy's art in New York, October 20, 2013. (Photo by Carlo Allegri/Reuters)

Some women doing yoga pose on the hammocks during the Anti-Gravity yoga class at Svarga e-Motion Sanctuary at Dharmawangsa Square, Jakarta, Saturday, April 18, 2015. Anti-Gravity Yoga or “aerial yoga”, is a new type of yoga, originating in New York but now being practised in several countries, which combines the traditional yoga poses, pilates and dance with the use of a hammock. (Photo by Jurnasyanto Sukarno/JG Photo)

In Mumbai, the windows of new high-rise apartment blocks, old low-rise residential buildings and shantytown shacks portray the disparity in living conditions and incomes in the Indian city. Rents for a place to live range from more than $2,000 to less than $5 a month. Here: Windows and doors of an old residential building are pictured in central Mumbai October 10, 2014. The cost for buying a residential apartment in Mumbai close to the city centre ranges from 12,000 Indian rupees ($ 200) per square feet to 112,552 Indian rupees ($ 1800) per square feet. (Photo by Danish Siddiqui/Reuters)

Hindu priests wash the head of a buffalo calf which was sacrificed as part of a ritual at a temple during the Durga Puja festival in Agartala, India, October 10, 2016. (Photo by Jayanta Dey/Reuters)

Charcoal burner Zygmunt Furdygiel fires wood inside a charcoal furnace at a charcoal making site in the forest of Bieszczady Mountains, near the village of Baligrod, Poland October 27, 2016. (Photo by Kacper Pempel/Reuters)

In this September 17, 2010 file photo a little brown bat is photographed in La Crosse Wis. Researchers for the first time found that little brown bats appear to be showing resistance to white-nose syndrome, which has killed millions of bats across North America. (Photo by Peter Thomson/La Crosse Tribune via AP Photo)

President Calvin Coolidge rides in a car during his inaugural parade in Washington, D.C., U.S. in March 1925. (Photo by Reuters/Library of Congress)