7. Kew Gardens
The Kew Gardens are the world’s largest collection of living plants. Founded in 1840, the garden’s collection includes more than 30,000 different kinds of plants. The herbarium has over seven million preserved plant specimens. The gardens also include a sizable library, which contains over 750,000 volumes and 175,000 prints and drawings in the illustrations collection.
The gardens are one of London’s top tourist attractions and were placed on the UNESCO list of World Heritage Sites in 2003.