2) There is a lake underneath the mersey rail tunnel that is fresh water NOT salt..
i am to belive this is true and i am also led to belive there are tours of the mersey tunnels and u can get to see this lake
also here is some brief History
about the tunnels :-
Brief Historical Background In 1922 Sir Archibald Salvidge tabled a motion in the Liverpool City Council to enquire into and report on the feasibility of either a tunnel or bridge to improve traffic facilities across the Mersey.
The Engineers' report emphatically supported a tunnel. They pointed out that a high level bridge, whilst adding to the appearance of the port and river, in the event of war would prove a susceptible target and if subject to a direct hit could lead to the closure of the Port of Liverpool. A bridge would be impossible to safeguard. Furthermore, the cost of continuous painting and the maintenance repairs to the bridge and its furniture would be astronomical. It was reported that a double-deck road tunnel would cost less to construct and offer considerable economy in maintenance.
On 8 August 1925, Royal Assent was given to a Private Bill authorising the project, and the setting up of the Mersey Tunnel Joint Committee. On 16 December 1925 HRH the Princess Royal switched on the power to the pneumatic drills and formally inaugurated an undertaking without parallel in engineering History
Construction The Queensway Tunnel was opened by King George V on 18 July 1934. Costing £8 million to construct over eight years and eight months, it ranked financially as the biggest single municipal enterprise ever undertaken in the country.
The pilot heading met under mid-river with a divergence of less than one inch. Hundreds of men worked in grim conditions to excavate 1,200,000 tons of rock and gravel. This was replaced with 82,000 tons of cast iron and 270,000 tons of concrete.
A million bolts tightened the iron lining and some 140 miles of joints were caulked. Some of the rubble was used in the building of nearby Otterspool promenade, which was part of a scheme to reclaim the land along parts of the foreshore of the Liverpool side of the River Mersey.
The main tunnel is 44 feet in diameter, and carries four lanes of traffic for just over two miles between Liverpool and Birkenhead.
There are two branch tunnels one of which, the Birkenhead Dock Branch (which at one time carried traffic to and from the Birkenhead Dock Estate), is now closed.
The Liverpool Dock Branch is still in operation for exit traffic only into the Liverpool Docks area.
To ventilate the traffic space above the roadway, fresh air is drawn in from outside the tunnel at six ventilation shafts - three on each side of the river - and is pumped at a uniform pressure into the tunnel through a continuous slot situated immediately under the kerb of the footways on both sides of the roadway.
Gases and vapours emitted by vehicles are blown along the length of the traffic space, drawn out through six exhaust ducts in the tunnel roof and discharged, by way of the high exhaust towers, into the outer atmosphere.
"Kingsway" Construction During the 1950's, because of the post-war boom in motoring and the expansion of local industry, the need for a second crossing became evident. Detailed studies of cross-river traffic flow provided definitive evidence of the need for an additional crossing. The arguments as to the most appropriate form of crossing, bridge or tunnel, investigated at great length in the early 1920's were repeated, and the same conclusion agreed; there was to be a second tunnel and in 1965 Royal Assent was given for the reconstitution of the Mersey Tunnel Joint Committee.
In January 1966, work commenced.
The Kingsway Tunnel, which was opened by Queen Elizabeth II in June 1971, is a twin tube tunnel, each "tube" has two traffic lanes twelve feed wide (compared to nine feet wide in the Queensway Tunnel) and is slightly under two miles in length.