Happy birthday, Metro! 39 years ago today, Metro opened its first 4.2 miles of service along the Red Line, stretching from Rhode Island Avenue to Farragut North.

The road to that point wasn’t easy. Discussions about opening a subway system in D.C. date back to the end of World War II, but the Washington Metropolitan Area Transit Authority wasn’t created until February of 1967. Construction for the Metro didn’t even start until three years later, meaning it took about six years for that first 4.2 miles of rail to finish construction.

On the opening day, around 50,000 people stood in line for hours to hop on the train for a free ride. As The Writer’s Almanac notes, “so many people tried to cram into the cars that the doors wouldn’t shut, and the trains stalled.” Look how far we’ve co—wait, never mind.

Here’s video of Metro trains operating in their first week of service: