The secretive indri (Indri indri) of Madagascar, the largest living lemur. It is also critically endangered and highly evolutionarily distinct with no close relatives, which makes its branch one of most precarious on the mammal evolutionary tree. In the likely event that the indri goes extinct, we will lose 19m years of unique evolutionary history from the mammal tree of life. (Photo by Pierre-Yves Babelon/Aarhus University)

A Thai and foreign revelers battle with water guns during the annual Songkran celebration at Khaosan Road, a tourist spot in Bangkok, Thailand, 12 April 2017. The four southeast Asian nations of Myanmar, Thailand, Cambodia and Laos started the Buddhist new year, known as Thingyan in Myanmar and Songkran in Thailand, on April 13. (Photo by Rungroj Yongrit/EPA)

Shaymaa Ismaa’eel, a 24-year-old Muslim woman passes by a group of angry protesters at an Islamic conference in Washington, DC on April 21, 2019. In response, she crouched in front of them and flashed a peace sign. The photo, posted on Instagram, prompted an outpouring of support. (Photo by Shaymaa Ismaa'eel/Instagram)

In this Wednesday, April 3, 2019, photo, children play in the water on a beach as a mosque collapsed during the Sept. 28, 2018, earthquake is seen in the background in Palu, Central Sulawesi, Indonesia. The earthquake spawned a large localized tsunami that wiped out coastal areas, while liquefaction caused by the shaking turned entire neighborhoods into rivers of sludge. The disaster killed thousands of people, making it the world’s deadliest seismic event in 2018. (Photo by Tatan Syuflana/AP Photo)

A girl in an angel costume walks with her family past vegetable vendors in Havana, Cuba, Wednesday, April 10, 2019. (Photo by Ramon Espinosa/AP Photo)

Police officers hold a revolver as they offer prayers to their weapons as part of a ritual at their headquarters on the occasion of Dussehra, or Vijaya Dashami, festival in Ahmedabad, India, October 8, 2019. (Photo by Amit Dave/Reuters)

A barber cuts hair of his client at a shuttered market during the countrywide traders strike in Lahore on October 29, 2019. Pakistani traders have joined hands to observe a nationwide shutterdown strike against the government over its “anti-business” policies, seeking to bring trade and economic activities across the country to a standstill on October 29 and 30. (Photo by Arif Ali/AFP Photo)

A home-made steam train, designed by Pavel Chilin, rides on a make-shift railway across country house neighborhood in the settlement of Ulyanovka in Leningrad region, Russia on November 4, 2019. (Photo by Anton Vaganov/Reuters)