The Post Office Built Around a Highway

Ahead on your right, the building that swallows an entire eight lane expressway is so enormous that engineers never bothered building around the highway. They simply left a hole straight through its base and let the road run underneath.

This is the Old Chicago Main Post Office, expanded in nineteen thirty two into a structure of roughly two and a half million square feet, among the largest postal buildings ever built in the country. When planners later routed what became the Eisenhower Expressway through the heart of downtown, the post office already stood directly in the way. Rather than move the road or the building, designers simply ran the highway through an opening left in the post office's base, so today eight lanes of traffic pass beneath floors that once held mail sorting machines.

The building kept working for decades, but by the nineteen nineties it had become outdated and inefficient to operate. The postal service moved its operations across the street into a newer facility in nineteen ninety seven, and the old giant went dark. For roughly the next twelve years it sat almost entirely empty, a colossal, mostly forgotten structure looming over the expressway, too large and too expensive for most developers to even consider.

Eventually a new owner took it on, pouring hundreds of millions of dollars into gutting and rebuilding the interior while preserving the limestone exterior. Today the building that once stranded engineers into tunneling straight through it holds offices for a changing roster of major companies, proof that in Chicago, even a building too big to easily reuse can eventually find a second life.