Ngorongoro Crater (Tanzania). At 610m deep and 260 sq km, this is the largest unflooded caldera in the world. A blue-green vision from above it's a haven for engangered wildlife and Maasai livestock. The crater was formed three million years ago when a giant volcano, which could have been as high as Kilimanjaro, exploded and collapsed. The caldera formed the concentric fractures in the crust cracked down to a magma reservoir deep underground. (Photo by John Bryant/Getty Images)

In this Thursday, February 14, 2019, photo, a Transformer's Bumblebee mascot helps a woman carries paper bags at a shopping mall in Handan in north China's Hebei province. U.S. and Chinese envoys are holding a second day of trade talks after the top economic adviser to President Donald Trump said he has yet to decide whether to go ahead with a March 2 tariff increase on imports from China. (Photo by Chinatopix via AP Photo)

In this July 8, 2019, photo, a monkey pulls on the clothes of Saraswati Dangol as she arrives to feed monkeys in the forest near Pashupatinath temple in Kathmandu, Nepal. For the past four years, Dangol has been bringing the bread every day to feed the monkeys. As soon as they see her with her white sack, they gather around her, some patiently waiting for their turn while others less patiently snatching the bread from her hands. Many of Dangol's regulars are elderly, or are mother or baby monkeys who are unable to fight for their share of food in the wild. (Photo by Niranjan Shrestha/AP Photo)

A demonstrator runs between burning tires during a curfew, two days after the nationwide anti-government protests turned violent, in Baghdad, Iraq on October 3, 2019. (Photo by Wissm al-Okili/Reuters)

Aerial view of a giant sinkhole on June 09, 2021 in Santa María Zacatepec, Mexico. The giant sinkhole is located 20 kilometers northwest from the capital city Puebla, the hole now measures 110 meters across its widest point, covering around 11,000 square meters and damaging a house built near the place where it appeared. Farmers of the surroundings have been affected since they are not allowed to enter their fields due to the warning perimeter set up by the authorities. (Photo by Hector Vivas/Getty Images)

Vancouver Canucks centerZack MacEwen (71) fights with Winnipeg Jets defenseman Derek Forbort (24) during first-period NHL hockey game action in Vancouver, British Columbia, Sunday, February 21, 2021. (Photo by Jonathan Hayward/The Canadian Press via AP Photo)

A man walks past a neon soaked street scene mural titled “Belfast – Blurry Eyed” by Dan Kitchener, also known as DANK on March 1, 2018 in Belfast, Northern Ireland. (Photo by Charles McQuillan/Getty Images)

An Afghan boy walks past a destroyed Russian-made tank, in Kabul, Afghanistan on February 24, 2020. (Photo by Mohammad Ismail/Reuters)