I would definitely recommend going on the London Eye if you go to London. The London Eye is a huge Ferris Wheel which takes about 30 minutes to go entirely around. I have been on the Eye twice (once during my family’s first trip to London and once this last time). This trip, we went just as the sun was setting (actually the last pod before the Eye closed for the night). The previous time we went during the middle of the day. If you are staying in London for a while I would try both because you can see London in different lights!