The California Academy of Sciences is one of the ten largest natural history museums in the world, and one of the oldest in the United States of America. It is located in Golden Gate Park in San Francisco. The Steinhart Aquarium and the Morrison Planetarium are housed within its walls. The Academy began life in 1853 as a learned society and still carries out a large amount of original research, with public exhibits and education becoming significant endeavours in the 20th century. The Academy's main buildings in Golden Gate Park are closed for major refurbishment until 2008, though it has reopened in temporary accommodation at 875 Howard Street since May 1, 2004.