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)

Shimmering clearest blue and stretching as far as the eye can see, this is one of Iceland's famed crystal ice caves. The giant solid waves look frozen in time but they are slowly moving along as part of the Vatnajokull Glacier – which stretches across eight per cent of the island. The images were captured in February 2014 by British photographer Rob Lott, 49. Photo: A wide view of Rob Lott in the crystal ice cave in the Vatnajokull Glacier, Iceland. (Photo by Rob Lott/Barcroft Media)

Participants in the Grelka Fest at the Sheregesh resort in Tashtagolsky District of Kemerovo Oblast, Russia on April 22, 2017. Russian girls marked the end of the ski season with a record-breaking bikini ski festival at Siberia’s top winter resort, Sheregesh. Some 1,498 skiers and snowboarders undressed to impress in the annual event as they took to the pistes under blues skies and sunshine in a bracing temperature of just 5°C. (Photo by Grelka Fest/The Siberian Times)

A stork-billed kingfisher (Pelargopsis capensis) is seen perched on a tree during monsoon rain on July 25, 2016 in Bintan, Indonesia. The stork-billed kingfisher is a tree species which is widely but sparsely distributed in the tropical Indian subcontinent and Southeast Asia, from India to Indonesia. This kingfisher is resident throughout its range. It is very large, measuring 35 to 38 cm (14 to 15 in) in length. The adult has a green back, blue wings and tail, and grey head. (Photo by Sijori Images/Barcroft Images)

They might look like something straight out of a horror film, but these extraordinary images have been created to show the special bond between cats and their owners. Photographer Sebastian Magnani, 28, from Brig, Switzerland, took pictures of dogs and their owners using the same position and camera settings before working his magic with editing software. The result is this startling set of images, which show the pooches with human clothes – one wearing a hoodie, another with a red coat, one with a shirt and cardigan, and another with a blue jacket. (Photos by Sebastian Magnani)

Looking for an escape from the daily realities of crisis-ridden Venezuela, Carmen Gomez finds solace receiving visitors on the roof of her Caracas apartment building every morning: groups of blue and gold macaws that arrive at daybreak. Here: A macaw lands in Carmen Borges' hand while she stays at a rooftop of a building in Caracas, Venezuela, June 12, 2019. (Photo by Manaure Quintero/Reuters)