Tower Bridge

Tower Bridge is one of the most recognised structures in the world — a Victorian bascule and suspension bridge that has spanned the Thames since 1894. Despite being commonly mistaken for London Bridge (a persistent mix-up that has confused tourists and, famously, at least one American buyer of the wrong bridge), Tower Bridge is the one with the twin Gothic towers, the blue ironwork, and the hydraulic lifting mechanism that still raises the roadway to let tall ships through. It sits at the eastern edge of the City of London, just downstream from the Tower of London, and it remains a working bridge that carries traffic every day.

The Tower Bridge Experience, as the ticketed attraction is called, takes you inside the structure itself. You walk the high-level glass-floored walkways connecting the two towers at 42 metres above the river — look down and you'll see buses, cyclists, and the occasional tall ship beneath your feet. The engine rooms down at river level house the original Victorian steam-powered hydraulic machinery, which was used to raise the bridge until 1976, and the exhibition explains how the whole mechanism works with surprising clarity. The bridge still lifts around 800 times a year; if you time your visit right, you can watch the roadway rise for a passing vessel.

Book tickets online in advance — walk-up queues can be substantial in summer, and the timed-entry system means you could wait longer than you'd like otherwise. The views from the walkways are genuinely spectacular and worth the modest entry fee, but the bridge itself is free to cross on foot at any time. For the best overall experience, combine a visit with a walk south along the riverbank toward Bermondsey or north through St Katharine Docks, both within easy walking distance.