Greenwich is only 7 miles from the center of London, easily reached by city bus, which is how we went.  It is the home of the Royal Observatory and the associated National Maritime Museum.  Greenwich is world famous because it sets the time benchmark for the world as "Greenwich Mean Time."  It also is the location of the Prime Meridian, which is zero degrees of longitude.  In fact the original Prime Meridian can be seen as a stainless steel ribbon that goes through the pavement outside the Royal Observatory and also right through the building. (A new meridian, representing more modern calculations, is about 100 meters east of this one.) The Queen's House which is now part of the National Maritime Museum is next to it.  Construction of this building started in 1619 by the architect Inigo Jones as a gift by King James I for his wife, Anne of Denmark.  It was finished in 1629 as a gift from King Charles I for his wife, Henrietta Maria.  The Royal Naval College and the Cutty Sark, the last merchant clipper ship, also are nearby. (Note:  The Cutty Sark was severely damaged by fire in May, 2007.  Reconstruction is planned. Check on the web site below for information.) It is pretty safe to say that Greenwich has about as great a concentration of interesting and historic attractions in a relatively small area as can be found anywhere.  And admission to most of these is free.

 

The Royal Observatory building, designed by Sir Christopher Wren, was built originally for the first Astronomer Royal, John Flamsteed, to house his instruments used to document the motions and positions of stars and planets.  It was begun in1675. Flamsteed's instruments are still there.

 

On the top of this building is a large red "time ball" installed in 1833 to send a time signal at exactly 1 PM each day, to the ships anchored in the Thames and about to sail off to all corners of the world.  When they saw the red ball drop they were able to set their chronometers, an essential step for them to be able to determine their exact positions in longitude on their voyage.  This was made possible by a Yorkshire carpenter turned clock designer, John Harrison, who succeeded in developing a clock that kept accurate time at sea.  The original Harrison chronometers are part of the National Maritime Museum's collection which you can inspect on line.

If you are interested in the Harrison saga in developing the chronometer, there is a very good  A&E made-for-television movie, titled "Longitude"  starring Michael Gambon and Jeremy Irons (review).