The Royal Observatory in Greenwich Park stands tall like a beacon of time, housing the prime meridian (longitude 0° 0' 0''). When you purchase a ticket, you gain access to its many attractions, including the Christopher Wren–designed Flamsteed House - named after the first Royal Astronomer - and the Meridian Courtyard, where you can stand with one foot in each hemisphere. Inside the observatory, with its distinctive onion-domed design, is the Great Equatorial Telescope (1893) and the Weller Astronomy Galleries, where you can explore space and time.