Place where wild and sometimes domesticated animals are exhibited in captivity. Aquatic zoological gardens are called aquariums. The first zoos were perhaps associated with domestication. Pigeons were kept in captivity as early as 4500 BC; other animals (e.g., elephants and antelopes) have also been kept in captivity since antiquity. Animal collections were kept by Charlemagne and other European monarchs. Hernán Cortés described a zoo in Mexico (1519) so large that it required a staff of 300. Modern zookeeping started in 1752 with the founding of the Imperial Menagerie at Vienna's Schönbrunn Palace. Open-range zoos were first established in the early 1930s, some so large that visitors drive through in cars, as on an African safari. There are now more than 1,000 animal collections open to the public throughout the world (e.g., in the U.S., the Bronx Zoo and San Diego Zoo).