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)

This absolute hero came to the rescue when flash floods in a World Cup city left two women stranded in their submerged cars. Here: A woman is rescued from a car after a flash flood in Nizhny Novgorod, Russia on June 19, 2018. (Photo by Lucy Nicholson/Reuters)

First place, Portrait. Three flat-coated retrievers – Crew, Darcie and Pagan – by Carol Durrant from the UK. (Photo by Carol Durrant/Dog Photographer of the Year 2018)

A cave diver in Anhumas Abyss, Bonito, Brazil. (Photo by Marcio Cabral/Epson International Pano Awards 2018)

Photographers help a Rohingya refugee to climb out of Naf River as they cross the Myanmar-Bangladesh border in Palong Khali, near Cox's Bazar, Bangladesh on November 1, 2017. (Photo by Hannah McKay/Reuters)

Camel herders scoop up water in plastic buckets from one of the few watering holes in the area, to water their animals near the drought-affected village of Bandarero, near Moyale town on the Ethiopian border, in northern Kenya, Friday, March 3, 2017. The U.N. humanitarian chief, Stephen O'Brien, toured Bandarero village on Friday and called on the international community to act to “avert the very worst of the effects of drought and to avert a famine to make sure we don't go from what is deep suffering to a catastrophe”. (Photo by Ben Curtis/AP Photo)

New York City Deputy Police Commissioner John A. Leach, right, watching agents pour liquor into sewer following a raid during the height of prohibition, circa 1921. (Photo by Tom Marshall/Mediadrumworld)

US freestyler, gold medalist Mcrae Williams competes during the men' s SlopeStyle (SS) finals at the FIS Snowboard and Freestyle Ski World Championships 2017 in Sierra Nevada on March 19, 2017. (Photo by Albert Gea/Reuters)