A group of African chimpanzees hug one another in glee as they take their first tentative steps outside after being locked up for 30 years. 

The animals were kidnapped as babies and flown to Europe where they spent three decades being used in a long series of laboratory experiments. 

Their ordeal finally ended in September 2011 when the 38 surviving chimps were released into an Austrian sanctuary called Gut Aiderbichl.