The Thames Tunnel was the world's first underwater tunnel, excavated beneath the River Thames in London between 1825 and 1841 and opened on 25 March 1843. It was built by Marc Isambard Brunel and his son Isambard Kingdom Brunel. 35 feet wide (11 m), 20 feet (6 m) high and 1,300 feet (396 m) long, it runs between Rotherhithe and Wapping at a depth of 75 feet (23 m) below the river's surface at high tide. It was originally designed for horse-drawn vehicles, but the tunnel company ran out of money to construct the ramps down to the tunnel and it was opened as a pedestrian tunnel.

In 1863, the tunnel was purchased by the East London Railway company for conversion to a railway tunnel. The first trains ran through the tunnel in 1869. From 1884 Metropolitan Railway and District Railway services used the tunnel and it later became part of the London Underground's Metropolitan line and finally it's East London line. In 2007 the tunnel was closed whilst the East London line was converted to become part of the London Overground network. It was reopened in 2010. Recognising its architectural and engineering importance, the tunnel is a Grade II* listed building. (Full article...)