5. Visit The Smallest Cathedral In London

The bite-size house of worship was created to represent the discipline of architecture; the other themes include agriculture, engineering, pottery, fine art, sciences, education and, er, local government. You'll need to peer over the side of the bridge to see the sculpture - or head underneath it on a boat - but it'll be worth it for the potential to impress or bamboozle other tourists when they ask you if you have visited St Paul's and you reply with an authoritative "which one?"
4. Walk Up The Monument

We can assure you that it still offers all the thrills you would expect from an open air viewing platform, especially on a windy day. The downside is that there is no elevator, so you have to negotiate 311 narrow stairs to get to the top, but it does provide a unique view of the city, hemmed in as it is by the modern monoliths that now surround it. You even get a special certificate at the end, and all for the princely sum of £3. The Monument is open daily from 9.30am until 5.30pm and 6pm in summertime.