Spectators pose for a selfie before the running of the Melbourne Cup at the Flemington Racecourse in Melbourne, Australia, Tuesday, November 6, 2018. (Photo by Andy Brownbill/AP Photo)

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 protester gestures during a “Yellow vest” protest against higher fuel prices during clashes on the Champs-Elysees in Paris, France, November 24, 2018. (Photo by Benoit Tessier/Reuters)

John McEnroe kicks back a television camera that he felt was crowding him on the court during the finals of the U.S. Pro Indoor Tennis Championships in Philadelphia January 27, 1985. McEnroe defeated Czech Miroslav Mecir to win the tournament. (Photo by Amy Sancetta/AP Photo)

A stroller walks his dogs in an autumnally colored forest in Cuxhaven, nothern Germany on November 7, 2018. (Photo by Patrik Stollarz/AFP Photo)

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)

General Maurice Gamelin, General Officer commanding the French Armies, is on a four day visit to England. He went to the staff college at Minley and is seen inspecting an anti-tank gun at Aldershot, on June 7, 1939. (Photo by AP Photo)

Firefighters carry a woman on a stretcher after a car drove into the crowded seaside boardwalk along Copacabana beach in Rio de Janeiro, Brazil, Thursday, January 18, 2018. Military police said on Twitter that at least 11 people were injured and that the driver has been taken into custody. (Photo by Silvia Izquierdo/AP Photo)