Thanks for all the great ideas. Just thought I’d respond back and let you all know how the 18 hours went. We did a lot in a short amount of time, and the weather couldn’t have been much nicer. Here’s the itinerary for the day:
Underground to Westminster Station
Walk by Big Ben and Parliament
Walk along the Thames and over to Trafalgar Square
Walk over to/through St. James Park
Walk by Buckingham Palace
Cross over into Hyde Park
Take a nap on the lawn with hundreds of other Londoners
Stumble upon the beautiful Princes Diana memorial (beautiful water feature that I’ve always seen in pictures)
Wind up in Notting Hill’s Prince Albert Bar for a leisurely drink/dinner
Underground back to Heathrow
All in all good trip! Those Brits sure do love their gardening and know how to use perennials well. Didn’t get to see much modern urban design on this trip, but that was okay. Thanks again for the thoughts everyone provided.