Back Bay Mill Dam is completed

Built by the Boston and Roxbury Mill Corporation, it is located under today’s Beacon Street from Charles Street to today’s Kenmore Square (then Sewall’s Point in Brookline).  Construction began in 1818.   Two stone walls fifty feet apart are built, and the space between them is filled, creating today’s Beacon Street (then Western Avenue). A similar cross dam is built on the line of today’s Hemenway Street and Parker Street. Originally a toll road, it is made free in 1865, renamed Beacon Street in 1857, and subsequently described by Oliver Wendell Holmes as, “The sunny street that holds the sifted few.” The dams were meant to power tide mills to be built on Gravelly Point (today’s Massachusetts Avenue area). However, only a few of the proposed mills were ever constructed, and the dams caused Back Bay to become very polluted.