All zoos are not created equal. Some do helpful, important conservation work and research, while others do the opposite -- imposing cruel conditions and inhumane treatment on captive animals. Keeping standards of compassionate care and humane treatment in mind, we've compiled the five zoos with the worst conditions for animals, the zoos that should be shut down.
1. Surabaya Zoo, Indonesia: Tiger fed with meat laced with formaldehyde
Often referred to in the media as "the world's cruelest zoo," the Surabaya Zoo has seen one tragedy after the next in recent years -- from a young lion found hanged in his enclosure and a giraffe with plastic lining her stomach to a tiger fed with meat laced with formaldehyde. A total of 43 animals died at the zoo between just July and September of last year. Journalist Richard Shears blew the lid off the zoo with his harrowing photos.