In the wake of the Great Depression, two wars, and at the dawn of the cold war, President Dwight D. Eisenhower viewed a 'national road' system as vital to the nation's interest on several counts: defense, commerce, safety, and unity. The Interstate Highway Act of 1956 created the vast network of superhighways, beltlines, and spurs of the modern-day highway system. More than 40,000 miles bound the 50 states together as an interconnected whole. The Interstate Highway System is an enduring marvel of conception, design, and construction. The undertaking became the largest public works program in American history, and its creation showcased the can-do American spirit of ambition, intelligence, and know-how.