Greenwich Foot Tunnel

The lowdown

Most people cross the Thames on a bridge or a tube. At Greenwich you can walk under it, for free, through a tiled Victorian tunnel that has carried people beneath the river since 1902. The glazed domed rotundas at each end are landmarks in their own right.

You descend by a wooden-floored lift or the spiral stairs, then walk the gentle curve of the tunnel, around three hundred and seventy metres of white tiles and echoes, under the full weight of the river above you. It is faintly eerie, completely free and open to pedestrians around the clock.

The real prize is the far side. Come up at Island Gardens on the Isle of Dogs and turn around for the classic free view back across the water to the Old Royal Naval College and the Queen's House, the picture Canaletto painted, framed by the river.