1956 – The Federal Aid Highway Act of 1956 is signed by U.S. President Dwight D. Eisenhower, officially creating the United States Interstate Highway System. The Federal Aid Highway Act of 1956, also known as the National Interstate and Defense Highways Act, Pub.L. 84–627 was enacted on June 29, 1956, when President Dwight D. Eisenhower signed the bill into law. With an original authorization of $25 billion for the construction of 41,000 miles of the Interstate Highway System over a 10-year period, it was the largest public works project in American history through that time. The addition of the term "defense" in the act's title was for two reasons: First, some of the original cost was diverted from defense funds. Secondly, most U.S. Air Force bases have a direct link to the system. One of the stated purposes was to provide access in order to defend the United States during a conventional or nuclear war with the Soviet Union and its communist allies.