The Singapore Zoo, also known as the Mandai Zoo or Singapore Zoological Gardens, is located along Mandai Lake Road in the Upper Seletar Reservoir catchment area. Dr Ong Swee Law, then-Chairman of the Public Utilities Board, pushed for the establishment of the zoo as a tourist attraction and as a way to connect children growing up in a rapidly urbanising Singapore of the 1960s with animals. The zoo was officially opened in June 1973 and initially housed over 300 species of animals. One unique feature of the zoo’s design is its "open-zoo" concept, pioneered by former zoo director Bernard Harrison, to ensure that animals are kept in spacious enclosures and separated from visitors by unobtrusive barriers. Notable attractions at the zoo include Children’s World, established in 1973 for children to interact with animals, and the Night Safari, which was the world's first night-time wildlife park when it opened in 1994. The zoo also has a well-regarded conservation and breeding programme for endangered species such as proboscis monkeys and orang utans.