Picture a perfect Boston block and a vision of Back Bay will likely spring to mind. Back Bay is the quintessential Boston neighborhood, boasting graceful streets lined with stately Victorian townhouses, the leafy allée of Commonwealth Avenue, the Charles River Esplanade, and the boutiques of Newbury Street. Back Bay was literally built on the back bay, in the marshes between Boston and Cambridge. In the mid-1800s, Boston had a shortage of luxury housing, and city planners came up with the idea of creating a new neighborhood to meet the need. And so, the tidal lands were filled in and architects designed an elegant neighborhood to fit: Wide tree-lined boulevards, inspired by Paris, form an orderly grid, while townhouses in shades of brick and brownstone flank the streets. Upon its completion, Back Bay immediately became a highly desired neighborhood and has remained so ever since.