Olympia is an exhibition centre and conference centre in West Kensington, on the boundary between The Royal Borough of Kensington & Chelsea and Hammersmith & Fulham, London, W14 8UX, England. It opened in the 19th century and was originally known as the National Agricultural Hall.
Opened in 1886, and built by Andrew Handyside of Derby it covered an area of 4 acres (16,000 m2). The Grand Hall, 450 feet (140 m) in length, by 250 feet (76 m) in breadth, was said to be the largest building in the kingdom covered by one span of iron and glass.
It now features three exhibition halls known as Olympia Grand Hall (19,325m² on two levels), Olympia National Hall (8,730m²), and Olympia 2 (7,850m² on three levels). Together with Earl's Court, these facilities are operated by EC&O Venues.
The nearest railway station is Kensington (Olympia) station which serves as both a London Overground station and a District Line station on the London Underground.

en.wikipedia.org/wiki/Olympia_(London)