The point of where Liverpool meets the Wirrel.
It was hailed as one of the great engineering triumphs and was Britain's biggest single municipal enterprise ever.
The Queensway Tunnel, the first road link under the Mersey was opened on 18 July 1934 by King George V after almost nine years of work.
Following the official opening the tunnel was opened for a celebratory walk which 80,000 people took part in, experiencing the novelty of being under the river bed.
To mark the tunnel's 75th anniversary it's once again being opened to the public to travel through on foot.
The special event on Sunday 19 July 2009 will raise money for local charity Claire House.
