Blackwall Tunnel

The Blackwall Tunnel is a pair of road tunnels under the River Thames in East London. They link the London Borough of Tower Hamlets with the Royal Borough of Greenwich. They are part of the A102 road.
For road traffic, the tunnel is one of the most important ways of getting across the Thames. It is crowded almost 24 hours a day, and a vehicle breakdown is close to being a major emergency.
The tunnel was originally a single-bore tunnel in 1897, with mainly horse-drawn traffic. It was doubled in 1967, years after this had been needed.
The northern approach is from the A12 road, and the southern approach is from the A2.