One part of “Celestrial Texts – Heavenly Tweets” by Laine Hogarty is seen as part of the “Hidden” annual sculpture exhibition at Rookwood Cemetery on September 15, 2014 in Sydney, Australia. Located in the suburb or Rookwood in Western Sydney Rookwood cemetery is the largest necropolis in the southern hemisphere. The Annual “Hidden” exhibition features works by local artists. (Photo by Mark Kolbe/Getty Images)

Roped up climbers leave the summit of Breithorn at 4,164 metres (13,661 feet) on the ridge marking the border with Switzerland (left) and Italy in the Alpine resort of Zermatt August 4, 2014. Switzerland will vote on November 30 on an initiative from the group Ecopop which proposes a cap on the number of immigrants. The group says it is motivated by concerns about a lack of living space exerting too much pressure on the land and natural resources, rather than by opposition to foreigners. (Photo by Denis Balibouse/Reuters)

“The power of nature”. Magma, ash and gas erupt from Mount Etna in December 2015, rising to a height of several kilometres. Winner: Nature. (Photo by Giuseppe Mario Famiani/SIPA Contest)

Pictures of deceased people are seen inside a chapel at a cemetery in the village of Smoljinac, Serbia, October 25, 2016. From a distance, the cemetery in the eastern Serbian village of Smoljinac looks like a residential neighbourhood eerily placed among graves. But once inside the grounds, after passing a section with the usual stone slabs, visitors find rows of small bungalows painted in pastel colours. They have one or two rooms, large windows and ornate plaques – some inside, some outside – memorialising the deceased. These are the burial chapels of Smoljinac, cosy cabins with a furnished room inside, a storage place for wreaths and funeral paraphernalia, and the family crypt below. Some even have electric power inside. (Photo by Marko Djurica/Reuters)

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)

Chris Staring photographs a mysterious train graveyard in the heart of southern Bolivia, where the skeletons of British steam locomotives and rail cars rust away on the edge of the world’s largest salt flats. More than 100 rail cars and locomotives can be found in different states of decay in the train graveyard. (Photo by Chris Staring/Rex Features/Shutterstock)

A man sits waiting for a train on the London Underground in 1890, when the platform floors were still made from wooden floorboards. (Photo by Hi-Story/Alamy Stock Photo)

A supercell that spawned a tornado earlier makes it was east north of McLean, Texas on April 16, 2015 in Texas, United States. Huge hail, terrifying lighting and giant supercells the size of buildings – these incredible images depict a year in the life of a storm chaser. Shot in 2015 by photographer Mike Olbinski, 40, this series of pictures show both the beautiful and the extreme nature of weather in the United States. (Photo by Mike Olbinski/Barcroft Media)