Following a period of maintenance and refurbishment the rail tunnel under the Thames was opened to the public to walk through.
This was the first tunnel to have been constructed underneath a navigable river and was built between 1825 and 1843 using the tunnelling shield invented by Isambard Kingdom Brunel and his farther Mark.
The tunnel was originally designed for horse-drawn carriages but instead was used by pedestrians and became a tourist attraction and reputedly a haunt for prostitutes. In 1869 it was converted into a railway tunnel.