Sanjay Gandhi National Park is a remarkable 104-square-kilometre forest that sits within the Greater Mumbai municipal limits, the world's largest protected forest within a metropolis. The park shelters leopards, deer, monkeys, reptiles, and over 250 bird species while being completely surrounded by one of the world's most densely populated cities. Entry is by ticket at the main gate in Borivali.
The park contains the Kanheri Caves — a complex of 109 Buddhist rock-cut caves used from the 1st century BCE through the 10th century CE — which are the park's main archaeological attraction. A toy train runs through part of the forest for families. The lion and tiger safari (an enclosed area) is popular with children but somewhat removed from the park's ecological significance. Early morning walks on the forest trails are excellent for birdwatching.