Tower Bridge has been opening up for ships since 1894, and although there aren't as many vessels on the Thames today, those bascules still open and close around 800 times per year.
We had the privilege of opening and closing the bridge, as the cruise ship Silver Wind passed beneath. Take a look:
Tower Bridge is owned and managed by the City of London Corporation. The bridge is one of the five City bridges of the City Bridge Trust, which donates money to many charitable causes, and whose roots hark back to the 13th century.