London has activities centuries in the making. It has some of the oldest buildings in the modern world with a lot of history going back to the times of the Romans. A visit to The British Museum shows some of this history. There are many sights and activities centered around the royal family with sites all over London.
London is littered with many amazing landmarks, from Big Ben to its many palaces and old squares. For something from this century, fans of Harry Potter will love the Warner Bros. Studio and getting a photo at Platform 9 3/4.
If you're willing to venture out of town a little bit, there's Stonehenge.