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 heavily tattooed Japanese woman poses for photographs near Asakusa Temple during the third and final day of Sanja Festival, on May 20, 2018 in Tokyo, Japan. Sanja Festival is one of Japan's major festivals and is held annually in the Asakusa area of Tokyo. (Photo by Carl Court/Getty Images)

Londoners enjoying the magnificent sight of sun setting perfectly in the middle of London Eye as seen from Greenwich Park in London, England on the warmest day of the year on April 19, 2018. (Photo by London Viewpoints/Rex Features/Shutterstock)

(L-R) Dustin Poirier punches Conor McGregor of Ireland in a lightweight fight during the UFC 257 event inside Etihad Arena on UFC Fight Island on January 23, 2021 in Abu Dhabi, United Arab Emirates. (Photo by Jeff Bottari/Zuffa LLC)

This photo taken late on February 21, 2021 in Milo, near Catania, Sicily, and obtained on February 22, 2021 from Italian news agency Ansa, shows lava flowing along the sides of the southern crater of the Etna volcano as a new eruptive episode of tall lava fountains, known as paroxysm, occurred. (Photo by ANSA/Handout via AFP Photo)

A moon light illuminates the sky through the clouds over a large line of grass between some home houses in the small village of Tafalla, northern Spain, Tuesday, May 1, 2018. (Photo by Alvaro Barrientos/AP Photo)

A cow is seen on land that used to be under water, at the Aculeo Lagoon in Paine, Chile, May 14, 2018. (Photo by Matias Delacroix/Reuters)

An Indian visitor sits on a bike with the wax statue of American actor Tom Cruise at the Madame Tussauds Delhi in New Delhi, India on June 6, 2018. (Photo by Money Sharma/AFP Photo)