Three examples of very dense high-rise housing developments suggest how the private market might have rebuilt parts of Manhattan for the middle class if the real estate boom of the late 1920s had not ended in the Great Depression. Two were created by the visionary developer Fred French: Tudor City (1927), a 14.5-acre enclave of a dozen towers on E. 42nd Street, and Knickerbocker Village (1934) on the Lower East side, which replaced some of the district’s oldest tenements with modern, but extremely dense, multifamily housing. The other, London Terrace (1930), packed 1,665 units into an avenue-long apartment block in Chelsea. The density of these middle-class developments averaged 463, 800, and 931 persons per acre, respectively. This story is adapted from an exhibition at the Skycraper Museum. The original version can be seen here.