Greenwich Royal Observatory - London

A couple sitting on a bench with the Greenwich Royal Observatory in the background.

The Greenwich Royal Observatory was founded by order of King Charles II to study astronomy and to fix longitude; see the page about the Prime Meridian. The oldest in the group of buildings comprising the observatory is Flamsteed House. It was built in 1675, with Sir Christopher Wren as the architect. It was built as a home for the first Astronomer Royal, John Flamsteed. He lived in the four rooms of the ground floor, and worked in the Octagon room above until his death in 1719. His successor in the office was Edmund Halley, famous for the comet that bears his name. Later Astronomers Royal lived there until 1948. The time ball on the roof was first erected in 1833, providing the first public time signal. At five minutes to one p.m. every day the ball rises half-way up the pole, reaching the top at two minutes to one. The ball drops at exactly one o'clock. Since the ball can be clearly seen from the river, ships have used the signal to check their time.