This ten-acre site was originally part of Skidmore, Owings & Merrill’s master plan for New York University–Bellevue Medical Complex. Developer William Zeckendorf bought the still-empty property in 1957 and hired Pei to design apartments for the open market. Pei consolidated 1,136 units into two 410-foot-long, 21-story offset slabs, perpendicular to the river and separated by a block-wide open green space. His entirely consistent, crisply detailed concrete-frame structures create urban-scale grandeur. Inside, they allow for generous layouts, although halls are long and apartments deep. The sculpture Pei wanted as a park centerpiece proved too costly, so the plaza has only dwarf trees, unlike at the elegant ensemble he designed for New York University, University Village (1966), where a Picasso is installed in the garden.