Part 4/9:

Moving further down, the depths are occupied by crucial utilities. Gas lines lie buried at depths between 12 and 24 inches, while telecommunications infrastructure is positioned even deeper. These essential services form the city’s life support system, running unnoticed underfoot — a reminder of how deeply woven infrastructure is into urban life.

Engineering Marvels

Below the essential utilities, at depths of around 6.5 feet, the real innovation of 19th-century engineering emerges — foundations upon which buildings were raised. The radical technique of lifting entire structures to build new foundations beneath them was first employed in 1858, making Chicago a pioneering space for structural engineering. This incredible feat became the foundation of the city’s architectural resilience.