Ariel Sharon Park (formerly a huge garbage dump)

The Hiniya Garbage Dump in Israel was comprised of 2,000 acres of garbage. It was converted beginning in 1998 to Ariel Sharon Park, and features a small amphitheater (with a 50,000-seat auditorium planned for 2014. Here's an article from Oregon Jewish Life about the park:

http://www.ojlife.com/2012/nov/israel/mountain-garbage-becomes-beautiful-park