The oldest section of the Greenwich Royal Observatory was commissioned by Charles II and built in 1675 under the stewardships of Sir Christopher Wren. The purpose of the exercise? To study astronomy and fix global longitude.

The Observatory is a spiritual home of time keeping. Where now stands a nuclear clock, dutifully providing a digital reading from the break down of radioactive material, there have been many lesser time keeping mechanisms.

Some of the old machines are incredible, including an remarkably accurate tower clock which is still in working order and loses but a couple of seconds a year. The buildings also houses some of the world's most powerful early telescopes. The Observatory has been a place of study, refuge and royal patronage for generations. It was such institutions that pushed the development of the sciences, and subsequently helped Britain establish itself as the world's technological superpower all those centuries ago.

A fascinating and beautiful place, and once you're done with the exhibits, take the time to walk up the park and admire the best natural view of the city this side of Hampstead.