In the first episode of a four-part series, “Mud” traces the roots of the residential highrise, from the biblical Tower of Babel to New York’s tenement buildings. In the second episode, “Concrete” explores how, in New York City and globally, residential high-rises and public housing attempted to foster social equality in the 20th century. The third episode “Glass” examines the recent proliferation of luxury condos and the growing segregation between the rich and poor, and the final episode, “Home”, comprises images submitted by New York Times readers, who show their lives in high-rises around the world. 3 4