Emily Hasler, an English Heritage employee at Charles Darwin's home, Down House, cleans a rabbit bone in his old study on April 2, 2011 in Downe, England. Staff at the house are cleaning and preparing the property ahead of their peak visitor season. The house contains the study where Darwin wrote “On the Origin of Species”, as well as family rooms and an extensive garden that inspired the renowned scientist. (Photo by Oli Scarff/Getty Images)

Baraa Melhem plays on her sisters bike at her mothers house on February 2, 2012 in Qalandia, near Ramallah, West Bank. Baraa Melhem was held in captivity in a bathroom by her father for over nine years, and was finally rescued by Palestinian security forces after a family member notified police. (Photo by Ilia Yefimovich/Getty Images)

Casey Stoner of Australia and Repsol Honda Team rounds the bend during the third day of MotoGP testing at Sepang Circuit on February 2, 2012 in Kuala Lumpur, Malaysia. (Photo by Mirco Lazzari gp/Getty Images)

Russian Mi-28N from the Berkuty (Golden Eagles) helicopter display team fly in formation during the “Aviadarts” military aviation competition at the Dubrovichi range near Ryazan, Russia, August 2, 2015. The aircraft started dipping down due to back propeller failure and crashed, killing one of two pilots, according to a Reuters photographer and official representatives of the competition. The aviation contest is part of the International Army Games, which are held in Russia from the 1st till the 15th of August with participants from 17 countries, according to organizers. (Photo by Maxim Shemetov/Reuters)

Ultra- trailers compete at sunrise on September 2, 2017 in Courmayeur, Italy, during the 15 th edition of the Mount Blanc Ultra Trail (UTMB), a 170 km race around the Mont Blanc crossing France, Italy and Switzerland. The 15 th Ultra- Trail du Mont- Blanc (UTMB) is a mountain ultramarathon with numerous passages in high altitude (>2500 m) and in difficult weather conditions (night, wind, cold, rain or snow). (Photo by Jeff Pachoud/AFP Photo)

A Humboldt penguin swims in a pool during the annual stock take at ZSL London Zoo in London, Thursday, January 2, 2020. Caring for more than 500 different species, ZSL London Zoo's keepers face the challenging task of tallying up every animal large and small, every mammal, bird, reptile, fish and invertebrate at the Zoo. (Photo by Frank Augstein/AP Photo)

A woman wearing a protective mask walks outside a church in Mandaluyong, east of Manila, Philippines on Sunday, February 2, 2020. The Philippines on Sunday reported the first death of a new virus outside of China, where authorities delayed the opening of schools in the worst-hit province and tightened quarantine measures in another that allow only one family member to venture out to buy supplies. (Photo by Aaron Favila/AP Photo)

In this image provided by the Pairi Daiza park, giant panda Hao Hao holds her newborn baby in her mouth at the park in Brugelette, Belgium, on Thursday, June 2, 2016. With the help of the Chinese government Hao Hao and her mate Xing Hui arrived in Belgium two years ago and Pairi Daiza adapted its park to build a bamboo forest for them. (Photo by Benoit Bouchez/Pairi Daiza via AP Photo)