If you're feeling a bit fragile or weepy, best give this video a miss.
This supercut shows a number of animals, including a group of chimpanzees who were kept in lab cages, a dog that had never felt grass before and a majestic lion released into the wild, had us all kinds of emotional.
*sniff* They're free now... *sniff*
Also, that tear-jerking orchestral music is NOT HELPING.
Via YouTube