Among London's many problems as it grew at the beginning of the nineteenth century was travel between the two banks of the river Thames, which held important ports that could accept shipping coming up the river from the channel. Bridges would interfere with that important trade, so in the years of the 19th century engineers began to examine the only other option: instead of going over, going under the river.
By September of 1944, the Western Allies had broken out of the Normandy beachehead, and suddenly and quickly moved across northern France . By September 7th, the 90th division was stretched across the northern sector on Patton’s Third Army’s left, advancing slowly northeast. As they did so the German defenders made a risky attack in an effort to spoil the allied advance, cutting through Allied lines in a surprise action at the small town of Mairy-Mannville.