Montgomery Zoo holds more than 500 animals, from five continents, in of barrier-free habitats. The Hank Williams Museum contains one of the largest collections of Williams memorabilia in the world. The Museum of Alabama serves as the official state history museum and is located in the Alabama Department of Archives and History building downtown. This museum was renovated and expanded in 2013 in a $10 million project that includes technological upgrades and many new exhibits and displays. The W. A. Gayle Planetarium, operated by Troy University, is one of the largest in the southeast United States and offers tours of the night sky and shows about current topics in astronomy. The planetarium was upgraded to a full-dome digital projector in 2014.