Joe Deedon, president of TAC ONE Consulting, demonstrates searching for a shooter in a middle school during an Active Shooter Response course offered by TAC ONE in Denver April 2, 2016. According to TAC ONE, the course, which is offered for the first time to concealed weapons permit carrying civilians, is designed at preparing people to effectively save lives prior to the arrival of law enforcement at an active shooter incident. (Photo by Rick Wilking/Reuters)

For more than three years, Ukraine has been plagued by a conflict between the eastern secessionist territories and the Kiev government. Demonstrations by pro-Russian parties that oppose the current government first began in 2014 - and now, over 10,000 people have died, many of them civilians. These images portray a generation caught between war and peace. Many of them were born into the civil conflict dominating the country and are disorientated about their place in the world. Here: Youths during a party organised on a decommissioned bridge in Kiev. (Photo by Aude Osnowycz/The Guardian)

Stunning images show the rolling splendor of the "iceberg capital of the world" under auroras. The photographer even includes himself in many of the shots – a signature of his that offers a fresh take on the conventional selfie, as well as providing a sense of scale to his works. Ziskas shot the photographs over a 10-day visit to western Greenland in September. Here: the photographer even includes himself in many of the shots – a signature of his that offers a fresh take on the conventional selfie, as well as providing a sense of scale to his works. (Photo by Paul Zizkas/Caters News)

A photo from Madonna’s high school yearbook at her childhood home in Rochester, Michigan, circa 1973. (Photo by Rebel Images/Rex Features/Shutterstock)

The first seal pup to be born this season at a major colony of grey seals on the Farne Islands sits beside its mother on Brownsman Island, England on September 30, 2015. (Photo by Owen Humphreys/PA Images)

In this February 2, 2015 photo, tourists jump as they pose for a picture, after disembarking from the Ocean Nova cruise ship, on King George Island, Antarctica. This tourist season, which runs November through March, more than 37,000 visitors are expected to walk on the coldest continent on Earth, about 10 percent more than the year before. (Photo by Natacha Pisarenko/AP Photo)

A pangolin carries its baby at a Bali zoo, Indonesia, Thursday, June 19, 2014. The pangolin baby was born on May 31. (Photo by Firdia Lisnawati/AP Photo)

Karis, an eleven week old lion cub, plays in fallen leaves brushed up by keepers in her enclosure at Blair Drummond Safari Park, near Stirling, Scotland, on November 20, 2013. (Photo by Andrew Milligan/PA Wire)