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)

With her husband, Brazil's new President Jair Bolsonaro in the background, Brazil's new first lady Michelle Bolsonaro gives a military salute from the Planalto Presidential palace, in Brasilia, Brazil, Tuesday, January 1, 2019. (Photo by Silvia Izquierdo/AP Photo)

Thai LGBT community participates in Gay Freedom Day Parade in Bangkok, Thailand on November 29, 2018. (Photo by Soe Zeya Tun/Reuters)

People perform Chinese Lion dance in Chinatown during the Chinese Lunar New Year in Lima, Peru on February 5, 2019. (Photo by Guadalupe Pardo/Reuters)

Soldiers on exercise in Kenya. The image, by Sergeant Dek Traylor, is among the section winners in the UK Army Photographic Competition 2018. (Photo by Sergeant Dek Traylor/PA Wire Press Association)

In this handout provided by the National Aeronautics and Space Administration (NASA), SpaceX's Falcon 9 is moved to the launch pad prior to the rocket's Thales Alenia Space launch attempt on April 26, 2015 in Cape Canaveral, Florida. (Photo by NASA via Getty Images)

Residents watch volcanic smoking and ashes rising from Mount Sinabung during an eruption in Karo, North Sumatra, Indonesia, February 24, 2016. Authorities have repeatedly called on local residents to remain patient in dealing with the impact of Sinabung's eruptions, which some experts have predicted will continue for five more years. (Photo by Xinhua/Barcroft Media)

A group of fashionable nonagenarians pose for a photo in Pengzhou, Sichuan, China on October 12, 2016. (Photo by Rex Features/Shutterstock)