I visited this WHS in June 2013. I used the underground and walked by the Cutty Sark, the Naval College, the Discover Greenwich information centre and up to the Royal Observatory and Park. The museum is very interesting and helps you appreciate the site better. I took a quick photo on the prime meridian line and saw the red ball drop at around 11:30. An interesting half day trip from London City Centre and it certainly deserves WHS status.