Tower Bridge

Everyone calls it London Bridge, and everyone is wrong. Tower Bridge is the one with the towers, the one that opens, and the one that took eight years and 432 workers to build. It was opened by the Prince of Wales on 30 June 1894 after a construction process that consumed over eleven thousand tonnes of steel and required the laying of seventy thousand tonnes of concrete.

The word "bascule" comes from the French for "seesaw," which is exactly how this bridge works — two massive arms pivot on an axis to lift and let ships pass through. In its first year alone, the bascules were raised 6,194 times, an average of seventeen times a day. The original mechanism was powered by steam-driven hydraulic pumps, and those gorgeous Victorian engines are still on display in the old engine rooms. The system was converted to oil and electricity in 1976, but the fundamental engineering remains a marvel.

The high-level walkways between the two towers were designed so pedestrians could cross even when the bridge was raised. In practice, they became notorious as gathering places for prostitutes and pickpockets, and were closed in 1910. They didn't reopen until 1982, when the Tower Bridge Exhibition reclaimed them as viewing galleries — now with glass floors that let you look straight down at the traffic and river forty-two metres below.

Tower Bridge is often confused with its plain neighbour upstream, but there's no mistaking the two up close. This is Victorian engineering at its most theatrical — a bridge designed to look medieval while hiding state-of-the-art industrial machinery inside its Gothic towers. It was, and remains, a bridge built to impress.