A century ago, a couple hired two giants of design, Frank Lloyd Wright and Jens Jensen, to envision homes and a landscape for their rolling, ravine-cut property near the bluffs of Lake Michigan north of Chicago. Trace the development of this collaboration, "Ravine Bluffs," a neighborhood of six Wright-designed houses in Glencoe, Ill. The lecture, featuring preservation consultant Gwen Sommers Yant, will take place at Unity Temple, 875 Lake St., Oak Park. $8 and free for Frank Lloyd Wright Trust members and volunteers. Register at flwright.org/programs/enrichment2.