Although this vast collection was part of the zoo's appeal, it may also have been one of the main causes of its financial problems. This contributed to the zoo being faced with closure in the 1980s. Due to the public change of attitude to animals kept in captivity and unsuitably cramped space, the zoo also suffered dwindling visitor numbers. However, when it was announced that London Zoo would close in 1991, a swell of public support in visitors and donations allowed the zoo to continue its work, attempt to balance its books, and take on the huge task of restoring its buildings and creating environments more suitable for animal behaviour in the late 20th century.