The Smithsonian-affiliated National Museum for American Jewish History (NMAJH), the nation’s only museum documenting the Jewish-American experience, has assiduously expanded its collection from 40 objects, when it opened in 1976, to more than 20,000. In doing so, it has outgrown the meager 6,000 square feet of exhibition space in its current home, a half-block from the spot on Philadelphia’s Independence Mall where it is constructing a new 100,000-square-foot complex designed by Polshek Partnership. NMAJH hopes that when the $150 million space opens on July 4, 2010, it will be able to expand its programming and quintuple its attendance to 250,000 visitors a year.

Polshek’s design for the National Museum for American Jewish History calls for two box-shaped volumes to sit atop a street-level pedestal of granite (top); one volume will be clad in terra cotta, conveying permanence and protection, while the other will be clad in glass, symbolizing a more subtle message of impermanence and fragility. Interior staircases and other circulation elements bridge the two volumes (above).