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 man dressed as Darth Vader goes through the turnstile at Lermontovsky Prospekt station on the Moscow metro in Moscow, Russia on May 4, 2017. (Photo by Vyacheslav Prokofyev/TASS)

A giraffe appears almost to be doing the splits as it bends to drink at a watering hole on a reserve in Mkuze, South Africa in September 2023. (Photo by Peter Batty/Solent News)

A little girl rubs her tired eyes during the first day at the lyceum named after Moldovan writer Gheorghe Asachi in Chisinau on September 2, 2024. (Photo by Dumitru Doru/Radio Free Europe/Radio Liberty)

Staff of a boat restaurant on the Taedong River line up at the entrance as they wait to greet customers Sunday, June 18, 2017, in Pyongyang, North Korea. The boat is berthed along the river, which is the fifth longest river on the Korean Peninsula and runs through the country's capital, Pyongyang. (Photo by Wong Maye-E/AP Photo)

Cambodian children sleep on a pavement at a park in Phnom Penh on July 8, 2016. (Photo by Tang Chhin Sothy/AFP Photo)

Ballerina Kira Hilli of the Netherlands National Ballet dances in a tutu with a diameter of 3 meters for a video made for the 1.5 meter society, on the Prinsengracht in Amsterdam, The Netherlands, 04 June 2020 (issued on 12 June 2020). The so-called social distance tutu is made of denim fabric, specially made for the Safe Distance Ballet. (Photo by Remko de Waal/EPA/EFE)

Students on their way home from school play in a river which has risen due to recent seasonal rains, in a remote village in Panca, Aceh province on January 22, 2021. (Photo by Chaideer Mahyuddin/AFP Photo)