the Giant Banyan
At the Kolkata Botanical Gardens. It is in the Guiness Book of Records it is so big (it covers an area of 3.9 acres and has a circumferance of over 450 metres). Banyans are a type of fig which send roots down from their branches to the ground, where they take hold and grow into new trunks and gradually spread outwards. The one here looks like a forest of trees because you are literally surrounded by trunks (it has 3618 prop-roots!), but they are all one tree. The original centre trunk no longer exists though, having been removed in 1925 after it was infected with fungus following some storm damage.