Tower Bridge.

Detail of Tower Bridge.

One of the towers of Tower Bridge.

Tower Bridge.

We happened to be sitting on a bench by the Thames when the bridge opened.

Boat passing beneath the open Tower Bridge.

Tower Bridge closing after a boat has passed through.

The tall boat that made the Tower Bridge open. It's called the [url=http://www.thamesbarge.org.uk/barges/charter/TChydrogen.html]Hydrogen[/url].

Tower of London, viewed from across the Thames.