Commonly referred to as the "T," the Massachusetts Bay Transportation Authority (MBTA) is the public transportation system in Boston. The subway system consists of four lines, each known by a color: Green, Red, Blue, and Orange. The closest subway stations to the Laboratory of Computer Science (LCS) are "Charles/MGH" on the Red Line and "Bowdoin" on the Blue Line. The closest handicap-accessible station is "Haymarket" on the Green Line.
Red Line: From the "Charles/MGH" station, walk east on Cambridge Street, and turn left (north) on Staniford Street.
Blue Line: From the "Bowdoin" station, walk west on Cambridge Street, and turn right (north) on Staniford Street.
Green Line and Orange Line: From the "North Station" (handicap-accessible), walk southwest on Causeway Street. When Causeway Street ends, continue slightly left (south) on Staniford Street.

Courtesy of MBTA (used with permission)