What a grueling day today.  We took a 10-hour tour though all of London:
St. Paul's Cathedral - very nice and pleasant, but very warm
The Changing of the Guard at Buckingham Palace - crushing crowds
Lunch at THE MEDIEVAL FEAST
The Tower of London - three hours and still very warm
A Thames cruise for ~30 minutes.
The London Eye - a 30-minute ride on a GIANT Ferris wheel
A lovely Italian dinner in an air-conditioned cellar restaurant
Tube ride back to the hotel.

Some highlights below:
Buckingham guards:

Leslie meets Sir Isaac Newton at the Tower:

The Houses of Parliament as seen from the top of the Eye 

Off to bed now.