Piccadilly Circus is a road junction and public space of London's West End in the City of Westminster. It was built in 1819 to connect Regent Street with Piccadilly. In this context, a circus, from the Latin word meaning "circle", is a round open space at a street junction. It is surrounded by several notable buildings, including the London Pavilion and Criterion Theatre. Underneath the plaza is Piccadilly Circus Underground station, part of the London Underground system.