Efforts to improve the transport infrastructure of Glasgow post-World War II were hit by the problem of crossing the Clyde.16 miners operated the shield working shifts in a compressed air environment to ensure that the rock and the river above did not collapse into the tunneling area.The digging itself would be done only with great difficulty due to the geology of the area, hard rock sitting under a soft silt layer beneath the river.A popular game amongst local children, and some adults, is attempting to hold one's breath for the duration of the journey by motorized vehicle through the Clyde Tunnel.The breath-holding game was the subject of Scottish artist Roderick Buchanan's video Gobstopper, for which he won the Beck's Futures art prize in 2000.