Thames Barrier

These strange metallic coccoons are the Thames Barrier, which spans 520 meters of the River Thames and protects the city of London from flooding. If there's a threat of a tidal surge from the ocean, the barrier's 10 steel gates are raised into position to keep the high water from reaching the city.

The barrier was built in 1982 near Greenwich, and there's a small park and information center there for visitors. Sarah and I went yesterday -- she wanted to see the Thames Barrier because it featured in an episode of "Dr. Who," though when we got there she said she didn't recognize it. (A lot of our sightseeing is being dictated by "Dr. Who." For example, we're supposed to go see a phone box somewhere near the Earl's Court tube station that most closely resembles the tardis. Who knew?)

Here you can see the London skyline, including the pointy Shard on the left, Canary Wharf in the middle and the Millennium Dome, looking like a flattened sea urchin. After checking out the barrier we took the tube to Canary Wharf, another "Dr. Who"-related stop, which is mostly just a collection of modern glass-and-steel bank buildings. I felt like I was in Charlotte, N.C.

Then we walked along the south bank of the Thames and took a tour of the reconstruction of Shakespeare's Globe Theatre. We continued over the river on the Millennium Bridge, and past St. Paul's before catching the tube to meet Dave near Regent's Park. The three of us had dinner and went to a brilliantly surreal and bawdy outdoor production of "A Midsummer Night's Dream." It rained pretty steadily right up until curtain time, but the rain miraculously stopped just in time for the show, so we didn't have to endure rescheduling and all that rigmarole. Whew!