The Back Bay Center  The Boston Back Bay Center was a proposed large development project proposed by Walter Gropius and The Architects Collaborative in the Boston's Back Bay in 1953. The plan was proposed be built on an abandoned rail yard. It was to contain four large office buildings, a shopping center, a convention hall, a hotel and a motel. The project was ultimately prevented from moving forward due to the nature of the tax base in Boston at the time, and many years later the property was purchased by Prudential where the Prudential Center stands now.