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)

An attendee dressed as Junkrat from the game Overwatch poses for a picture during opening day of pop culture convention Comic Con International in San Diego, USA on Thursday, July 19, 2018. (Photo by Mike Blake/Reuters)

Aoife Ni Heochaidh enjoys the sunrise as she welcomes winter solstice at the 5000-year-old stone age passage tomb of Newgrange in the Boyne Valley, as entry inside the chamber is closed for the second year due to coronavirus disease (COVID-19) pandemic, in Newgrange, Ireland, December 21, 2021. (Photo by Clodagh Kilcoyne/Reuters)

Italian movie star Gina Lollobrigida shows a 0.95 super-grand-angle lens mount on a 35mm camera, as she presents her collection of photographic equipment at her home on the ancient Appian Way on the outskirts of Rome, July 2, 1964. (Photo by Girolamo di Majo/AP Photo)

A person looks at Australian artist Ron Muecks large-scale installation “Mass” which comprises more than 100 hand-cast skulls that collectively weigh approximately 5000 kilograms at an exhibition at the National Gallery of Victoria (NGV) in Melbourne on May 18, 2022. (Photo by William West/AFP Photo)

“They're some of the most intriguing and complex creatures on the planet but they really do have nothing to hide – because theyre totally see-through. Transparent animals – creatures with clear glass-like skin – can be found all over the world but their very existence is still shrouded in mystery. The fascinating organisms verge on the invisible and their translucent skin often helps them elude predators”. – Caters News. Photo: Thornback Skate. (Photo by Ken Lucas/Caters News)

Some of the best entries so far in the 2016 Insight Astronomy Photographer of the Year competition. There are two weeks left to enter, and the winners will be announced in September. Here: Aurora over Laksvatn Fjord, Laksvatn, Norway. The aurora borealis dances in the skies over the town of Laksvatn, with the Milky Way to the left. The image is a single shot with no compositing, only post-processing to bring out the aurora, and some colour corrections. The photographer Matt Walford said: “I love the way the northern lights look like they are just wistfully dancing over the fjord, framed by the mountains on either side”. (Photo by Matt Walford/National Maritime Museum)

A climate change activist plays a violin in Times Square as Manhattan is shrouded in haze and smoke which drifted south from wildfires in Canada, in New York City, New York, U.S., June 7, 2023. (Photo by Maye-E Wong/Reuters)