The Washington, DC Metro opened on this date in 1976, 40 years ago today. Over the years, Metro was the first or among the first transit systems in the United States to accomplish several things, such as automated trains, carpeted floors on the trains, and a variable fare scheme. In addition, the high arched concrete vaults have become a symbol of Washington’s architecture. Over the past 40 years, the system has been built out past its originally planned 101 miles with extensions to Largo and Reston, and a further extension to Dulles Airport and Loudoun County is now under construction. The new 7000 series cars that are now being delivered will bring about the retirement of the 1000, 4000, and 5000 series cars. However, despite the changes in the offing, Metro has established itself as a critical part of the DC area’s transportation network. With it’s use by resident Washingtonians and visiting tourists alike, it truly is America’s subway. Happy birthday Metro and here’s to the next 40 years!