An army tank fires during a firefight against militants linked to al Qaeda near the southern Yemeni city of Zinjibar May 30, 2012. (Photo by Reuters/Yemen's Defence Ministry)

The Chernobyl disaster was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine, which was under the direct jurisdiction of the central authorities of the Soviet Union. The Chernobyl disaster is the worst nuclear power plant accident in history in terms of cost and resulting deaths, and is one of only two classified as a level 7 event (the maximum classification) on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster in 2011). Photo: Graffiti of a crying baby on a wall, Chernobyl Power Plant, Chernobyl, Ukraine. (Photo by Hans Neleman/Getty Images)

An unknown number of guns are being built with the mechanisms, causing problems for the police and ATF officials. Photo: An ATF agent holds a generic unfinished receiver, back, and one that has been manufactured, front, at an ATF field office in Washington, on May 06, 2014. The ATF is trying to crack down on the trade in the makeshift guns by targeting shops and individuals who offer to turn the unfinished receivers into functional pieces for firearms. (Photo by Bill O'Leary/The Washington Post)

A view of the Sheikh Zayed highway in Dubai and some high rise buildings, November 8, 2007. (Photo by Steve Crisp/Reuters)

Rock and roll musician Elvis Presley during a press conference after his first performance at the International Hotel in Las vegas, Nevada on August 1, 1969. (Photo by Michael Ochs Archives/Getty Images)

Photographer Mihaela Noroc travelled the world from Ethiopia to the US and from Guatemala to France in search of natural and authentic beauty. She introduces some of the inspiring women she met on her journey. Here: Ecuador. “More and more tribes of Amazonia are starting to adopt modern clothes for everyday life. But they are still keeping their traditional clothes for important events. I photographed this young woman in her wedding outfit”. (Photo by Mihaela Noroc/The Guardian)

A Los Angeles County Fire helicopter flies over during the “Skirball Fire” which began early morning in Bel-Air, California, USA, 06 December 2017. An outbreak of several fires North of Los Angeles has occurred as one of the strongest Santa Ana winds forecast of the season is ongoing and expected to last several days. (Photo by John Cetrino/EPA/EFE)

The International Garden Photographer of the Year is one of the world’s premier competitions specialising in botanical photography. There are 11 main categories and numerous special awards including Young Garden Photographer of the Year, and the mobile-only category Gardens on the Go. Here: Winner, Wildflower Landscapes category. Alto Paraíso de Goiás, Goiás, Brazil. (Photo by Marcio Cabral/The Guardian)