Boston-area is loaded with them. Within 10 miles of Boston’s Downtown Crossing (which includes many, very dense adjacent cities) it’s unquestionably the most d

Boston-area is loaded with them. Within 10 miles of Boston’s Downtown Crossing (which includes many, very dense adjacent cities) it’s unquestionably the most dominant type of building for residences. Duplexes, triplexes and tenements dominate any decent sized city (100K+) in Massachusetts. It’s just what tends to happen when cities were founded 350-400+ years ago.