Tour Montparnasse

The Tour Montparnasse sits directly atop one of the busiest subway junctions in the city, the Montparnasse Bienvenue station. Because the tower weighs so much, engineers had to construct a massive, reinforced concrete shield to protect the active metro tunnels beneath it. The building rests on fifty-six pillars that burrow seventy meters into the ground, a necessity to support its immense structure in Paris’s sandy soil. This foundation design was a radical engineering feat for its time, allowing the skyscraper to exist without compromising the transit network running deep below.