Tower Bridge

London’s most famous bridge was built between 1886 and 1894 to carry East End traffic across the river without blocking ships on their way to the port. The City architect Horace Jones designed it with the engineer John Wolfe Barry: two Gothic Revival towers clad in Cornish granite and Portland stone hide the steel skeleton and the hydraulic machinery that lifts the bascules, driven by steam engines until 1976 and by electric motors since.

In 1952 a double-decker bus was halfway across when the bascule started to rise: the driver floored it, jumped the gap and landed on the other side with everyone on board. The company gave him a ten-pound bonus. Today you can go up to the high walkways, which since 2014 have glass floor sections for looking down at the Thames under your feet.