The United States spent hundreds of billions of dollars on building out a cross-country Interstate highway system. Building ...

Praised as one of the greatest public works project in American history, the Interstate Highway System is about to turn 70.

Story continues below map of former mines in New Jersey. What is under Route 80's lanes? The problem, however, may have far more to do with how and where the highway was built than by whom.

Praised as one of the greatest public works project in American history, the Interstate Highway System is about to turn 70.

Praised as one of the greatest public works project in American history, the Interstate Highway System is about to turn 70.