Mentioned by Lonely Planet Top Choices
Top things to do in London, England
"Opened in 1828, London Zoo is among the oldest in the world. The emphasis nowadays is firmly on conservation, breeding and education, with fewer animals and bigger enclosures. Highlights include Land of the Lions, Gorilla Kingdom, Tiger Territory, the walk-through In with the Lemurs and Penguin Beach. There are regular feeding sessions and talks, various experiences are available, such as Keeper for a Day, and you can even spend the night in the Gir Lion Lodge."