An ancient oak tree sits in a Shropshire field as the first signs of Spring begin to show across the United Kingdom on February 19, 2014 in Bridgnorth, England. (Photo by Christopher Furlong/Getty Images)

Members of a teenage girl gang convincing an unwilling recruit to join the gang, circa 1955. (Photo by Vecchio/Three Lions)

Renowned aerobatic pilots Sean D. Tucker, flying the Oracle Challenger III, and Jeff Boerboon, flying the Jack Link's Screamin' Sasquatch, take to the skies over EAA's 2015 AirVenture Oshkosh, on Monday, July 20, 2015 in Oshkosh, Wis. (Photo by Matt Ludtke/AP Images for Jack Link's)

Young migrants gesture during a day of solidarity organised by local organizations and resdients for asylum seekers at a makeshift camp outside the foreign office in Brussels, Belgium September 6, 2015. Over 150,000 people seeking to enter Europe have reached Hungary this year, most coming through the southern border with Serbia, and many apply for asylum but quickly try to leave for wealthier EU countries. (Photo by Yves Herman/Reuters)

A group of people are seen on a Victoria line train in London, England during the first night of the Night Tube service on August 19 2016. The Central line and Victoria line are the first to operate a Night service with further lines expected to be running by the end of the year. (Photo by SWNS.com)

A photographer could bear-ly believe his eyes when a bear started waving at him. The friendly animal wandered to the front of his enclosure before sitting back in full view of zoo guests. He then lifts his powerful paw and excitedly waves in an almost human-like way at his new audience. The hilarious encounter was captured by keen photographer Andrey Slepnev, 31, while on a trip to Madrid Zoo, Spain on March 24, 2016. (Photo by Andrey Slepnev/Caters News)

Strokkur geyser against cloudy sky at sunset. Strokkur is a fountain geyser located in a geothermal area beside the Hvítá River in Iceland in the southwest part of the country, east of Reykjavík. It is one of Iceland's most famous geysers, erupting once every 6–10 minutes. Its usual height is 15–20 m, although it can sometimes erupt up to 40 m high. (Photo by Teatsche Dijkhuis/Getty Images/EyeEm)