Taking you back to the Second World War

It became necessary to change route continuously because the ice was still thin. The drivers were plagued by heavy snowfalls and storms when visibility was almost nil. They often lost their bearings and the lorries would then plunge into unfrozen patches of water. In December 126 lorries sank in the lake. Pools also presented a great danger. Covered with snow, they differed little from thick ice in appearance, and so trail walkers had to mark them with stakes. Strips of unfrozen water several metres wide sometimes would stretch for many kilometres, and 147 bridges and causeways had to be built across them.