Commonwealth Avenue Mall

This guide to Commonwealth Avenue Mall in Boston starts with the ground itself, open tidal water two hundred years ago until a mill company dammed it in the 1820s and turned the bay into a stagnant flat. It follows the decades-long landfill project that buried the flat with sand and gravel hauled in from outside the city, and architect Arthur Gilman's 1856 plan for a French-style boulevard down the middle of the new land. Every townhouse along the mall had to be carried on wooden pilings driven down through the soft fill to reach something solid.