Fossil records indicate that this early lizard, Megalania (Megalania prisca or Varanus priscus), was a whopping seven metres in length. They were part of a megafaunal assemblage that inhabited southern Australia during the Pleistocene. The youngest fossil remains date to around 50,000 years ago. The first aboriginal settlers of Australia might have encountered them and been a factor in their extinction. (Photo by Sky TV/The Guardian)

In this October 15, 2014 file photo, Katsu Nakamura, sky division manager for Yamaha USA, moves the RMax unmanned helicopter into position before a demonstration of its aerial application capabilities at the University of California, Davis' Oakville Station test vineyard in Oakville, Calif. Researchers at UC Davis have been studying the effectiveness of the drone's ability for spraying pest control and nutritional materials on the test vineyard in California's Napa Valley. (Photo by Rich Pedroncelli/AP Photo)

A pair of ice climbers have been snapped in front of a stunning aurora. Mike Stuart and Takeshi Tani were climbing the Athabasca Glacier in Alberta, Canada, when the aurora lit up the nights sky. They were photographed by famed night-time photographer Paul Zizka, who specialises in photographing auroras in some of Canadas most beautiful parks. (Photo by Paul Zizka/Caters News)

A handout picture provided by the press service of MORTON Group of Companies, show the balloon of Russian adventurer Fedor Konyukhov in the sky during his solo round-the-world balloon flight just after taking off from a spot near Northam, 96 kilometres north-east of Perth in Western Australia, 12 July 2016. Fedor Konyukhov took off from Northam on 12 July 2016 in attempt to beat the record of 13 days of American aviator Steve Fossett. (Photo by EPA/Morton Press Service)

Neil Zeller's snaps were taken across Canada, where he photographs the northern lights dancing across a dark night sky. In one stunning shot, Zeller, 42, even manages to capture a flash of lightning beneath a storm cell while an aurora gives off a magnificent green glow. The photographer, from Calgary, Alberta, describes himself as a night person, and became interested in night photography about 10 years ago. (Photo by Neil Zeller/Caters News)

With the United Nations and Tudor City in the foreground, lightning strikes in the sky over the East River as a major storm approaches New York City July 2, 2014. Tropical Storm Arthur, the first of the Atlantic hurricane season, gathered strength July 20, 2014 and would likely reach hurricane strength over the next couple of days. (Photo by Timothy A. Clary/AFP Photo)

Winner. “This was taken in the South Ari Atolls, Maldives, as the south-west monsoon season was setting in. It features my partner – and dive buddy – Emma after surfacing at the end of the last dive of the day to find 1.5 metre swells and dark monsoon clouds. MICK RYAN, JUDGE: This beautiful portrait of a diver in an ocean swell below a menacing sky stands out this month for its emotional and elemental beauty. It is a reminder that while we may play among nature we are always dwarfed by its power and must be constantly on our guard”. (Photo by Simon Dunn/The Guardian)

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)