This is the site of Boston's first - and for a good while, only - flour mill. The Mill owners closed this pond off from the Charles River, leaving only a small stream that led to the ocean. Twice a day, the tides in Boston Harbour would fill the steam, powering the mill. Of course, closing the pond off also made it stagnant. Since water was used as a dumping ground for sewage, garbage and dead animals, it was quite dirty and frankly, stank.