The Rotherhithe tunnel in East London ( Lat 51.506452, Long -0.048615) is a road tunnel under the River Thames that connects Tower Hamlets in the north to Southwark in the south. It is primarily a tunnel for cars but there is a footpath although walking through it is only a journey for the brave or foolhardy.
The tunnel took 4 years to complete and opened in 1908 and consists of a single bore 15m below the high water level of the Thames. It isn’t straight and contains sharp ‘kinks’ in the roadway that can be quite unnerving to drivers especially when large vehicles are coming in the opposite direction.
A 20mph speed limit is enforced through the tunnel by average speed cameras, and in 2003 the tunnel was named the 10th most dangerous tunnel in Europe due to its outdated design and poor safety features by modern standards.
The above video is a short ride through on a motorcycle (a BME F800GS if you are interested) and captures a ride in both directions through the runnel.