Treasure Island is an artificial island in San Francisco Bay. Built in 1936 and 1937 for the 1939 Golden Gate International Exposition, the island's World’s Fair site is a California Historical Landmark. Treasure Island is connected by a small isthmus to Yerba Buena Island. Sea lions can be observed in the water from the shoreline, and the new Eastern span of the San Francisco - Oakland Bay Bridge can be observed from the Eastern part of the island. Treasure Island's old aircraft hangars serve as sound stages used in film and television productions.