Meet the star students of orangutan school – the unique rehab centre where orphaned apes are taught how to climb trees and survive in the wild without their mum and dad. (Photo by Caters News)

The phenomenon of the Hill of Crosses in northern Lithuania began when people started leaving crosses there hundreds of years ago – and continues to this day. These photos of a hill covered in crosses show the amazing sight it has become. Photo: In 1831 an unsuccessful uprising against the Russian czar left many rebels dead. Relatives of the dead rebels, with no bodies to bury, instead left crosses, according to the Daily Mail. (Photo by Richard Gardner/Rex USA)

Pro-Russian rebels stand near a monument during a ceremony to honour the World War Two defenders of Donetsk from Nazi forces, in Donetsk, in this September 8, 2014 file photo. (Photo by Marko Djurica/Reuters)

Children attend a war safety awareness class conducted by civil defence members, in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria May 14, 2016. (Photo by Khalil Ashawi/Reuters)

A man stands near bodies of his young relatives after an airstrike in the rebel held Douma neighbourhood of Damascus, Syria August 22, 2016. (Photo by Bassam Khabieh/Reuters)

Singer Madonna performs during her concert at the AccorHotels Arena in Paris, France, December 9, 2015, on her Rebel Heart Tour. (Photo by Benoit Tessier/Reuters)

A street vendor warms his foot around a fire during cold weather in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria, January 4, 2016. (Photo by Khalil Ashawi/Reuters)

A service member of the Ukrainian armed forces is seen at fighting positions on the line of separation from pro-Russian rebels in Donetsk region, Ukraine on April 10, 2021. (Photo by Oleksandr Klymenko/Reuters)