In this photo taken Tuesday, October 14, 2014, skulls and bones are stacked at the Catacombs in Paris, France. The subterranean tunnels, stretching 2 kilometers (1.24 miles), cradle the bones of some 6 million Parisians from centuries past and once gave refuge to smugglers. The site used to close at 5 p.m., but is now staying open until 8 p.m. The change is mainly aimed at allowing more people to visit and reducing long lines, since it can only hold a limited number of people at a time and visits can't be reserved in advance. (Photo by Francois Mori/AP Photo)

A flood affected family moves on a banana raft past a fishing net in Morigaon district, east of Gauhati, northeastern Assam state, India, Sunday, July 31, 2016. A week of heavy rain has killed dozens of people and uprooted tens of thousands of others from their homes. Floods are an annual occurrence in Assam and many parts of India during the June-September monsoon season. (Photo by Anupam Nath/AP Photo)

A DC-10 air tanker delivers flame retardant to the Blue Cut fire in Wrightwood, Calif., Wednesday, August 17, 2016. A wildfire with a ferocity never seen before by veteran California firefighters raced up and down canyon hillsides, instantly engulfing homes and forcing thousands of people to flee, some running for their lives just ahead of the flames. (Photo by Alex Gallardo/AP Photo)

Residents ride on top of an overcrowded “Jeepney”, a locally manufactured public transport, along a highway in Mogpog town on Marinduque island in central Philippines April 8, 2015. (Photo by Erik De Castro/Reuters)

Santa Jerry Julian of Colorado Springs, Colorado hides in the grass following a ride on the Polar Express during a field trip from the Charles W. Howard Santa Claus School in Midland, Michigan, U.S. October 28, 2016. (Photo by Christinne Muschi/Reuters)

“T'antawawas” (children's bread) are displayed in a popular market to commemorate All Saints Day in La Paz, October 30, 2016. (Photo by David Mercado/Reuters)

A ring-tailed lemur sunbakes at Melbourne Zoo in Melbourne, Victoria, Australia on December 21 2016. (Photo by Julian Smith/EPA)

In this July 5, 2016 photo, a tamed elephant rests in a pool of water by a road in Baduraliya, a village outside Colombo, Sri Lanka. Even as the country cracks down on illegal ownership, the enduring demand for elephants has the government planning to set up its own pool of captive animals to be hired out to temples for ceremonies and maintained with budget funds. (Photo by Eranga Jayawardena/AP Photo)