The Tower is London; that's what the advertisements on the Underground proclaimed when I first went to London in the late 1990's. I certainly wouldn't distill the city of London down to just one site, but I did enjoy my visit to the Tower. I don't remember much about the tour, but I remember seeing the historic White Tower, the walls of the fortress, a water-gate entrance from the Thames, the Yeoman Warders, and, of course, the Crown Jewels. Also of note were the ravens whose wings are clipped lest they escape and cause the British crown to fall. I remember a discussion about the imprisonment and death of Anne Boleyn from the tour, and since I've recently read Hilary Mantel's Wolf Hall and Bring Up the Bodies, I'd like to go back and take a tour again to see the Tower with fresher eyes. For that matter, I'd like to go back to get a better picture of the Tower.

Logistics: Easily accessible in London by Underground, bus, taxi, or foot. I like bus Route 15, myself.