Heritage Open Day: Georges Dock Building will open its doors for the weekend to let visitors see behind its Art Deco exterior. Tours of the building are available on the day on a first come first served basis. There will be a small display of artefacts and photographs. Explore behind the Art Deco exterior of the Georges Dock Building, which will be opening its doors for the weekend. At the time of its construction, the Queensway Mersey Tunnel was the largest underwater road in the world and the biggest municipal undertaking. Georges Dock Building is one of six ventilation stations for the tunnel and is also the most ornate as it was built to be the Head Office for the Mersey Tunnels.