Greenwich is a site that truly deserves its listing on the WHS. Apart from being very easy to reach from central London, Greenwich's importance in the fields of science, navigation, and world exploration is really universal. I first went there on a warm summer evening in 2002, when all the buildings were already closed, including the Royal Observatory with the Prime Meridian. It was still a great place for a stroll, but of course I had to return one day to see everything. Over 10 years later, I finally came back to London and made sure to set aside a full day for Greenwich and all its attractions. The first thing you see when you step out from the foot tunnel (recommended because you can see the full panorama from the opposite bank of the Thames) is the former tea clipper Cutty Sark which is really very interesting to visit. The Royal Observatory is a bit uphill in the large park, and you should time your visit to be in the courtyard at 1 p.m. to see the famous time ball drop. You will probably stand in line there anyway to get a chance at taking a picture of your feet straddling the Prime Meridian. Both the Observatory and the huge National Maritime Museum include very interesting exhibitions on science, navigation, and history. I also visited the Queen's House, the last remaining buiding of the former Royal Palace of Greenwich, as well as parts of the town's historic centre, also part of the WHS. Finally, the Old Royal Naval College with the Chapel and the Painted Hall, something I had missed entirely on my first visit, is an architectural masterpiece by Christopher Wren and definitely a must-see for any trip to London. One day is barely enough to take in everything Greenwich has to offer, and for anybody interested in history, science, and anything related to the sea, this is a fantastic and fascinating destination.