Fact 1: The longest known king cobra ever was a captive one at the London Zoo. It grew to around 18.8 feet (5.7 meters) before being euthanized upon the outbreak of WW2. (it was feared if the zoo was bombed, the snake may escape) Fact 2: The zoo's giraffe house is the oldest zoo building in the world still used for its original purpose. Fact 3: The London Zoo currently holds approximately 700 species, but is only 36 acres big.
Haha....this one is difficult. Well, maybe. This zoo was started when a museum director who kept animals in the museum backyard had residents in the city to complain about the noise and smell, forcing the animals to be moved to a farm that the government was planning to build a zoo there.