The U.S. Department of the Interior announced the designation of 13 new National Historic Landmarks earlier this spring. This designation signifies the importance of these sites in representing the nation’s heritage. Although the list contains many historic sites, such as the Japanese internment camp at Topaz, Utah, it also includes architecturally significant structures. Three buildings, for instance, showcase how Frank Lloyd Wright’s style changed during the course of his career. For more about the individual sites, please see the accompanying slideshow at left.