CCNY's Spitzer School of Architecture hosts an unprecedented exhibition on Antoni Gaudí's "unfinished masterpiece" — Sagrada Família, the basílica in Barcelona that generations of architects and builders have continued since Gaudí's death in 1926. George Ranalli, dean of the architecture school, talks about the world's longest-running construction project and how he brought to New York this rare collection of original drawings, plaster casts and other architectural artifacts that have never been out of Spain.