Armed police officers and soldiers strengthen their training in seawater in Fangchenggang City, Guangxi Province, China on July 24, 2023. (Photo by Costfoto/NurPhoto/Rex Features/Shutterstock)

In this photo taken on January 20, 2024 a tourist poses in front of incense sticks drying in a courtyard in the village of Quang Phu Cau on the outskirts of Hanoi. Families living and working in the “incense village” of Quang Phu Cau now also make sticks in yellow, blue and green, catering to visitors eager to snap shots for Instagram. (Photo by Nhac Nguyen/AFP Photo)

Visitors walk down the Bramante Staircase at The Vatican Museums, during a press tour at the Vatican on May 2, 2025. (Photo by Dimitar Dilkoff/AFP Photo)

A woman takes a photograph of the Martin Place Christmas Tree on December 17, 2024 in Sydney, Australia. Each year Sydney's landmarks and streets are adorned with festive lights and projections for the Christmas festive period. (Photo by Lisa Maree Williams/Getty Images)

Riot police stand guard behind a fire as refinery workers hold a blockade of the oil depot of Douchy-Les-Mines to protest against the government's proposed labour reforms, on May 25, 2016. Refinery workers stepped up strikes that threaten to paralyse France weeks ahead of the Euro 2016 tournament as the government moved to break their blockades, escalating a three-month tug-of-war over labour reforms. (Photo by François L.O./AFP Photo)

Stranded cars remain in a flooded street during an intense rainstorm in Havana, on April 29, 2015. Two people were killed, three buildings collapsed and another 24 suffered some kind of damage due to the heavy rain that affected several sectors of Havana Wednesday. (Photo by Yamil Lage/AFP Photo)

Police detain Sebahat Tuncel, co-chair of the pro-Kurdish Democratic Regions Party (DBP), during a protest against the arrest of Kurdish lawmakers, in the southeastern city of Diyarbakir, Turkey, November 4, 2016. (Photo by Sertac Kayar/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)