The US Interstate Highway System Was Inspired by Germany's Autobahn

America's 48,000-mile interstate highway system — one of the greatest infrastructure projects in human history — was directly inspired by Nazi Germany's road network. President Dwight D. Eisenhower had been deeply impressed by Germany's Autobahn during World War II and pushed for a similar American system after taking office.

Eisenhower signed the Federal Aid Highway Act on June 29, 1956, authorizing construction with a 90/10 federal-to-state funding split. The official name is the 'Dwight D. Eisenhower National System of Interstate and Defense Highways' — the defense rationale was that such roads could evacuate cities and move military equipment in a national emergency. Construction took over 35 years and cost roughly $500 billion in today's dollars.