The idea for a rail system in the nation’s capital was born in the 1950s. Since then, the Metro has become one of the largest public-works projects ever built as well as one of the busies rail transit systems in the nation. Still, it continues to grow with plans for the Purple Line and the second phase of the Silver Line.

Welcome to Curbed’s first-ever Transportation Week! From how to improve public transportation in cities, ranking the best car-free neighborhoods across the country, and a friendly competition between NYC, San Francisco, and Los Angeles to determine which has the best public transit, this week is all about how we get around in our favorite cities. All aboard!

With information compiled from WAMU, WMATA, The Washington Post, and author Zachary M. Schrag’s research, get a quick look at the history of D.C.’s rapid transit system with the timeline below.

Can’t see the timeline? Head here.