A conductor (C) collects fares from candy floss sellers as they travel in a tram to a marketplace early morning in Kolkata, India, December 23, 2015. (Photo by Rupak De Chowdhuri/Reuters)

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 Thursday, February 14, 2019, photo, a Transformer's Bumblebee mascot helps a woman carries paper bags at a shopping mall in Handan in north China's Hebei province. U.S. and Chinese envoys are holding a second day of trade talks after the top economic adviser to President Donald Trump said he has yet to decide whether to go ahead with a March 2 tariff increase on imports from China. (Photo by Chinatopix via AP Photo)

An Algerian demonstrator wearing face paint in the colours of the national flag takes part in an anti-government demonstration in the capital Algiers on November 1, 2019. Demonstrators converged on Algiers in their thousands for a massive anti-government rally called to coincide with official celebrations of the anniversary of the war that won Algeria's independence from France. (Photo by Ryad Kramdi/AFP Photo)

Makeup artist He Yuhong, also known as “Yuya”, checks herself in the mirror during a photo shoot following her transformation into the “Girl with a Pearl Earring”, the 17th century oil painting by Dutch painter Johannes Vermeer, at her house in Chongqing, China on August 14, 2018. (Photo by Thomas Suen/Reuters)

An artist gets ready backstage to perform an Indian art form of dance called “Ottamthullal” at the annual eight-day long Vrischikolsavam festival, which features a colourful procession of decorated elephants along with drum and trumpets concerts, at Sree Poornathrayeesa temple in Kochi, India, December 7, 2018. (Photo by Sivaram V/Reuters)

Workers pull apart a house in Khandyga, Russia, on February 2, 2018. The shifting ground caused by the uneven thawing of permafrost each summer causes buildings like this Soviet-era apartment house to sag and collapse. (Photo by Amos Chapple/Radio Free Europe/Radio Liberty)

Staff members clean the court during the Women's Preliminary Round - Pool B volleyball match between China and Argentina on day ten of the Tokyo 2020 Olympic Games at Ariake Arena on August 2, 2021 in Tokyo, Japan. (Photo by Carlos Garcia Rawlins/Reuters)