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)

A woman shouts asking for help during an eviction in Rio de Janeiro, Brazil, Friday, April 11, 2014. Squatters in Rio de Janeiro are clashing with police after a Brazilian court ordered that 5,000 people be evicted from abandoned buildings of a telecommunications company. Officers have used tear gas and stun grenades to try to disperse the families. (Photo by Silvia Izquierdo/AP Photo)

In this Thursday, August 17, 2017 photo, a troupe charges and fires their rifles during Tabourida, a traditional horse riding show also known as Fantasia, in Mansouria, near Casablanca, Morocco. Thousands gathered recently in Mansouria, a small town south of the capital Rabat, to attend one of the oldest festivals in Morocco. Nineteen horse troupes came from different parts of the kingdom to celebrate a three-day event that blends courage, skill and tradition. (Photo by Mosa'ab Elshamy/AP Photo)

Elderly women wait for customers as they sell their self-made food products at a street market, with a graffiti depicting Russian President Vladimir Putin on the wall of a house seen in the background, in the town of Kashira, outside Moscow, Russia on October 10, 2017. (Photo by Andrey Volkov/Reuters)

A mother raise her glass filled with 2017 Beaujolais Nouveau wine as she holds her child in a colored hot water “wine bath” at Hakone Kowakien Yunessun hot spring resort in Hakone, west of Tokyo, Japan, 16 November 2017, on the day of the Beaujolais Nouveau official release. With Germany and the United States, Japan is a major market for the Beaujolais Nouveau. (Photo by Franck Robichon/EPA/EFE)

Festival goers blow soap-bubbles at the 28th Sziget (Island) Festival on Shipyard Island, Northern Budapest, Hungary, 15 August 2022. The festival is one of the biggest cultural events of Europe offering art exhibitions, theatrical and circus performances and above all music concerts. (Photo by Marton Monus/EPA/EFE)

A woman in a wedding dress walks on the dried-up riverbed of the Jialing river, a tributary of the Yangtze, that is approaching record-low water levels in Chongqing, China on August 18, 2022. (Photo by Thomas Peter/Reuters)

U.S. President Donald Trump holds news conference on the coronavirus outbreak at the White House in Washington, U.S., February 26, 2020. (Photo by Carlos Barria/Reuters)