Tube passengers take a selfie next to a London underground roundel designed for the launching of the Night Tubes on display at Oxford Circus underground station in London, Britain, 19 August 2016. The long delayed Night Tubes service launched on 19 August. The 24-hour service will operate on Fridays and Saturdays. (Photo by Hannah Mckay/EPA)

A mahout rides an elephant at Tad Sae Waterfall outside Luang Prabang, Laos July 31, 2016. Protected by the United Nations cultural heritage agency UNESCO, Luang Prabang is one of the most alluring places in the region – a city that evokes old-world romance that has gained a reputation as a travellers' Shangri La. (Photo by Jorge Silva/Reuters)

Costumed characters participate in the 30th annual Dragon Con Parade in Atlanta, Georgia, USA, 03 September 2016. Thousands of attendees crowd downtown Atlanta hotels and streets during the Labor Day weekend for the Dragon Con science fiction and fantasy convention, many dressed as their favorite characters. (Photo by Erik S. Lesser/EPA)

Astronaut Donald R. Pettit would often rig an array of as many as six cameras in the cupola windows and set them all to fire continuously for events such as sunsets, which only last around seven seconds on the ISS. (Photo by Donald R. Pettit)

A participant in the Borodino Battle re-enactment before the show at the Borodino Field in the Moscow Region on September 4, 2016. The Battle of Borodino, fought on September 7, 1812, was a battle fought in the Napoleonic Wars during the French invasion of Russia. The fighting involved around 250,000 troops and left at least 70,000 casualties, making Borodino the deadliest day of the Napoleonic Wars. (Photo by Kirill Kallinikov/Sputnik)

A ring-tailed lemur is pictured at Zoom Torino, a zoological park in Cumiana near Turin, on April 22, 2015. Zoom Torino is a new immersive zoological park, where animals can be seen without bars or cages, only natural barriers ensure the visit. (Photo by Marco Bertorello/AFP Photo)

Sam Warren climbs in to a prototype combat vehicle during the PrepperCon expo Friday, April 24, 2015, in Sandy, Utah. Hundreds of survivalists and “preppers” are gathering in the Salt Lake City suburb of Sandy for the first annual PrepperCon, featuring demonstrations of underground bunkers, food storage, and armored vehicles. (Photo by Rick Bowmer/AP Photo)

A man carries the body of his son for burial after he was killed when a rooftop of his house collapsed due to heavy rain in the outskirts of Peshawar, Pakistan April 27, 2015. A severe storm in northwest Pakistan, dubbed a “mini-cyclone”, has killed 44 people and injured more than 200, officials said, raising their previous death toll. (Photo by Fayaz Aziz/Reuters)