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 picture made available on 08 July 2015 showsa lightning strikes during a heavy storm over Poznan in the night of 07 July 2015. Severe storms passed last night over Poland causing lots of damages to buildings, trees, electricity and railway tractions. (Photo by Lukasz Ogrodowczyk/EPA)

A girl uses her mobile phone during the evening at the National Park in Khartoum, Sudan, April 24, 2015. (Photo by Mohamed Nureldin Abdallah/Reuters)

A model wears a creation for the Elie Saab Spring-Summer 2022 Haute Couture fashion collection, in Paris, Wednesday, January 26, 2022. (Photo by Francois Mori/AP Photo)

Fireworks illuminate the Ampera Bridge during a New Year's Eve celebrations in Palembang, Indonesia on January 1, 2020. (Photo by Muhammad Tohir/Sijori Images via ZUMA Wire/Rex Features/Shutterstoc)

A worker sprays disinfectant as sanitization operations against Coronavirus are carried out in the museum hosted by the Maschio Angioino medieval castle, in Naples, Italy, Tuesday, March 10, 2020. (Photo by Alessandro Pone/LaPresse via AP Photo)

The sunken ferry Sewol sits on a semi-submersible ship during its salvage operations at the sea off Jindo, South Korea, in this handout picture provided by the Ministry of Oceans and Fisheries and released by Yonhap on March 26, 2017. (Photo by Reuters/Yonhap/The Ministry of Oceans and Fisheries)

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)