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)

Children dressed in festival costume sit on the huge paper doll of historical Japanese figure named Hashi-Benkeii on the carts during the Mikuini annual festival on May 20, 2014 in Sakai, Japan. The annual festival takes place from May 19-21 and is attended by thousands of visitors. During the festival people dressed in traditional Japanese costumes pull carts carrying 6 meter high dolls of Japanese historical figures through the narrow streets. The origins of the festival are unclear but its history can be traced back more than 250 years. (Photo by Buddhika Weerasinghe/Getty Images)

Tree trunks and rocks are set up to support a leaning wall of Li Yonghua's damaged cave house in an area where land is sinking next to a coal mine, in Helin village of Xiaoyi, China's Shanxi province, August 2, 2016. (Photo by Jason Lee/Reuters)

A man designs a face mask with the photograph of a customer printed on it, amid the spread of the coronavirus disease (COVID-19), at a photo studio in Gandhinagar, India, May 27, 2020. (Photo by Amit Dave/Reuters)

Nguyen Ngoc Anh, 36, who was an illegal logger turned forest protector poses at Phong Nha National Park, Quang Binh province, Vietnam on April 8, 2022. (Photo by Hoang Trung/Reuters)

Composer, harpist and singer Esther Swift alongside her Italian Salvi pedal harp during a photocall ahead of her upcoming tour, at the Forth Bridge in North Queensferry, Scotland on Tuesday, March 7, 2023. Ms Swift will tour across Scotland solo this month with a programme of original compositions and traditional works. (Photo by Jane Barlow/PA Images via Getty Images)

A migrant worker wearing face masks to help curb the spread of the coronavirus walks up to a pedestrian bridge in Beijing, Sunday, December 6, 2020. Provincial governments across China are placing orders for experimental, domestically made coronavirus vaccines, though health officials have yet to say how well they work or how they may reach the country's 1.4 billion people. (Photo by Andy Wong/AP Photo)

A girl competes in a hobby horsing competition in St. Petersburg, Russia, April 21, 2024. (Photo by Dmitri Lovetsky/AP Photo)