This photo taken on December 2, 2015 shows a lenticular cloud forming as white streaks from airplanes mark the blue sky, in a rare atmospheric phenomena above the town of Gevgelija on December 2, 2015. Lenticular clouds have been regularly confused for UFOs throughout history due to the their smooth, round or oval lens-shaped structure. (Photo by Armend Nimani/AFP Photo)

Layers of breathtaking colour streak the rolling hills of this vast desert, making the landscape appear as though it has been tie-dyed. The natural phenomenon, nicknamed the “Painted Desert”, was formed when the area was once a river floodplain. Each colour corresponds to a different underground geological feature – rocks which have seemingly dyed the layers of earth above. Formed from volcanic activity, the hills at the John Day Fossil Beds National Monument in East Central Oregon, USA, are almost bursting with colour. Pictured: The colourful hills at the John Day Fossil Beds National Monument in East Central Oregon, USA. (Photo by Mark Brodkin/Solent News/SIPA Press)

A Perseid meteor streaks across the sky over the community of Cold Creek on August 12, 2015 in the Spring Mountains National Recreation Area, Nevada. The annual display, known as the Perseid shower because the meteors appear to radiate from the constellation Perseus in the northeastern sky, is a result of Earth's orbit passing through debris from the comet Swift-Tuttle. (Photo by Ethan Miller/Getty Images)

These stunning pictures show a normally vicious tiger calmly swimming in a pool of algae, on Jule 9, 2014. The powerful cat takes a refreshing break by taking a dip in the bright green algae. But it looks like this big cat is scared of getting his head wet as he strains to keep it above the water. After splashing around for a bit the tiger gets out and tries to air-dry with specks of the vegetation dripping off his fur. The striking pictures were taken at Copenhagen zoo by snapper Soren Lundgren Neilson. (Photo by Soren Nielsen/Caters News)

“The Sumatran tiger (Panthera tigris sumatrae) is a rare tiger subspecies that inhabits the Indonesian island of Sumatra. It was classified as critically endangered by IUCN in 2008 as the population is projected to be 441 to 679 individuals, with no subpopulation having an effective population size larger than 50 individuals, with a declining trend”. – Wikipedia

This photo taken on July 25, 2012 one of 14 preserved bodies of critically-endangered Sumatran tigers seized as members of the Indonesian national police and the special crime unit inspect the scene at a warehouse in Cibubur, south of Jakarta. Indonesian police seized 14 preserved bodies of critically-endangered Sumatran tigers in a raid on a house near Jakarta, a spokesman said on July 19. (Photo by Bay Ismoyo/AFP Photo)

These zoo animals take on an altogether more sinister look after posing for a set of moody black and white portraits. Alex Teuscher has brought out the dark side in a range of exotic creatures with his artistic project which took two years to complete. Photo: White tiger. (Photo by Alex Teuscher/BNPS)

Fans cheer in the stands ahead of the CFL's 102nd Grey Cup football championship between the Calgary Stampeders and the Hamilton Tiger Cats in Vancouver, British Columbia, November 30, 2014. (Photo by Todd Korol/Reuters)