In the late nineteenth century, Pittsburgh's first plant conservatory was established on this site until it was destroyed by a natural gas explosion in the late 1920's. In 1952, the conservatory was rebuilt by the City of Pittsburgh and opened with the addition of birds to the indoor gardens. In 1968, the Aviary-Conservatory's largest exhibit, a walkthrough tropical marsh and six other exhibits were constructed which doubled the size of the institution. The Aviary was one of the first zoos to present its collection in free-flight rooms and natural exhibits with over 25,000 square feet of space. In the 1980's, the Aviary began to evolve its focus toward wildlife conservation by beginning the captive breeding of rare and endangered birds.