Kew Gardens is a botanic garden in southwest London that houses the "largest and most diverse botanical and mycological collections in the world". Founded in 1840, from the exotic garden at Kew Park, its living collections include some of the 27,000 taxa curated by Royal Botanic Gardens, Kew, while the herbarium, one of the largest in the world, has over 8.5 million preserved plant and fungal specimens. The library contains more than 750,000 volumes, and the illustrations collection contains more than 175,000 prints and drawings of plants. It is one of London's top tourist attractions and is a World Heritage Site.

London is the capital and largest city of both England and the United Kingdom, with a population of around 8.8 million, and its metropolitan area is the largest in Western Europe, with a population of 14.9 million. It stands on the River Thames in south-east England at the head of a 50-mile (80 km) estuary down to the North Sea and has been a major settlement for nearly two millennia. The City of London, its ancient core and financial centre, was founded by the Romans as Londinium and retains its medieval boundaries. The City of Westminster, to the west of the City of London, has for centuries hosted the national government and parliament. In the 19th century, London grew rapidly, becoming the world's largest city at the time, as it expanded and absorbed the neighbouring county of Middlesex, and parts of Surrey and Kent. In 1965 it was combined with parts of Essex and Hertfordshire to create the administrative area of Greater London, which is governed by 33 local authorities and the Greater London Authority.