Real estate developer Henry Mandel used high-rise density and collective amenities as a strategy for London Terrace, which stretched between Tenth and Eleventh avenues on W. 23rd Street. To create his behemoth block, Mandel demolished 80 historic row houses and multiplied the stories to 22, with 67 percent land coverage. With this strategy, Mandel housed a comparable density of turn-of-the-century tenements in modern apartments at an average of nearly 931 people per acre. London Terrace became the densest multifamily housing in the city, and garnered rents of $52-$130 per room.