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 March 31, 2019 photo, an Egyptian student borrows a Bedouin wedding dress to pose for a photograph with Bedouin men from the Hamada tribe, in Wadi Sahw, Abu Zenima, in South Sinai, Egypt. Four Bedouin women are for the first time leading tours in Egypt’s Sinai Peninsula, breaking new ground in their deeply conservative community, where women almost never work outside the home or interact with outsiders. The tourists can only be women, and the tours can’t go overnight. Each day before the sun sets, the group returns to the Hamada’s home village in Wadi Sahu, a narrow desert valley. (Photo by Nariman El-Mofty/AP Photo)

Syrian boys play with plastic guns on the first day of the Muslim religious festival of Eid al-Adha in al-Dana in Syria's rebel-controlled Idlib region, near the border with Turkey, on August 11, 2019. Muslims across the world are celebrating the first day of the Feast of Sacrifice, which marks the end of the hajj pilgrimage to Mecca and commemorates prophet Abraham's sacrifice of a lamb after God spared Ishmael, his son. (Photo by Aaref Watad/AFP Photo)

British actress Jameela Jamil arrives at the 2019 InStyle Awards at The Getty Center on October 21, 2019 in Los Angeles, California. (Photo by Steve Granitz/WireImage)

Nepalese army personnel pay tributes before the body of a person who died of COVID-19 before cremating the same in Kathmandu, Nepal, Monday, August 17, 2020. (Photo by Niranjan Shrestha/AP Photo)

A Saudi trader wears a mask as he monitors stock information at the Saudi stock market in Riyadh, Saudi Arabia on August 25, 2020. (Photo by Ahmed Yosri/Reuters)

(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)

White House Communications Director and presidential advisor Hope Hicks arrives at the U.S. Capitol Visitors Center February 27, 2018 in Washington, DC. Hicks is scheduled to testify behind closed doors to the House Intelligence Committee in its ongoing investigation into Russia's interference in the 2016 election. (Photo by Chip Somodevilla/Getty Images)