Go touristy at the Tower of London, the castle is set right on the river Thames and is simply spectacular. It will take a few hours to tour this building, but its so worth it. This is people were beheaded back in the old days, it's crazy to think that such shocking events occurred here. You'll ge to see the prisoner towers, crown jewels and even torture tools used once upon a time. Buy a 2 for 1 ticket deal at the train station.