Woolwich foot tunnel
The 493rd longest tunnel in the world
The Woolwich foot tunnel crosses under the River Thames in Woolwich, in East London from Old Woolwich in the Royal Borough of Greenwich to North Woolwich in the London Borough of Newham. The tunnel (open 24/7) offers pedestrians and cyclists an alternative way to cross the river when the Woolwich Free Ferry service is not operating. Both entrances to the tunnel (north entrance at 51°29′56″N 0°03′42″E and south entrance at 51°29′40″N 0°03′46″E) are Grade II listed buildings. The south entrance is somewhat hidden behind the Waterfront leisure centre. It is the oldest remaining building in the riverside area of Old Woolwich.
Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).