Fallingwater's monumental 1,800 square foot living measures roughly 40 by 50 feet and a central, symmetrical raised cove ceiling. The 23¾" x 18¼" x 60" wood coffee table was designed by Frank Lloyd Wright. The smaller tabonettes, a side table or occasional table, also designed by Wright, came in three sizes and all bearing a resemblance to their larger coffee table counterpart. The name, tabonette, came about from a mistaken transcription by one of Wright's apprentices who may misspelled the word taboret. The Zabuton, 25½" x 29¾" floor cushions, were designed by Frank Lloyd Wright in 1939. The High Hassocks, also designed by Wright, are taller versions of the Zabuton at 12" x 26" x 21¾". They represent one of the earliest uses of latex foam, a material suggested by Edgar Jaufmann Jr., in a residential setting. Surrounded by a walnut veneer frame, the floor cushions are upholsted with either a red or yellow, heavily textured, wool blend Jack Lenor Larsen fabric called Doria. The free floating seats of differing heights help create a casual environment. Fallingwater, sometimes referred to as the Edgar J. Kaufmann Sr. Residence or just the Kaufmann Residence, located within a 5,100-acre nature reserve 50 miles southeast of Pittsburgh, was designed by Frank Lloyd Wright and built between 1936 and 1939. Built over a 30-foot flowing waterfall on Bear Run in the Mill Run section of Stewart Township, Fayette County, Pennsylvania, the house served as a vacation retreat for the Kaufmann family including patriarch, Edgar Kaufmann Sr., was a successful Pittsburgh businessman and president of Kaufmann's Department Store, and his son, Edgar Kaufmann, Jr., who studied architecture briefly under Wright. Wright collaborated with staff engineers Mendel Glickman and William Wesley Peters on the structural design, and assigned his apprentice, Robert Mosher, as his permanent on-site representative throughout construction. Despite frequent conflicts between Wright, Kaufmann, and the construction contractor, the home and guesthouse were finally constructed at a cost of $155,000. A boulder top, rising unaltered above the level of the first floor, serves as the hearth of the 1,800-square-foot living room fireplace and the functional and spiritual heart of Fallingwater. To the left hangs a spherical Cherokee-red kettle that can be swung over the fire. The kettle, copied after one Frank Lloyd Wright used at Taliesin, was intended to serve mulled wine, but proved unworkable. The fireplace fork is signed by the master ironworker Samuel Yellin, who made it around 1930 for La Tourelle. Fallingwater was designated a National Historic Landmark in 1966. It was listed among the Smithsonian's 28 Places to See Before You Die. In a 1991 poll of members of the American Institute of Architects (AIA), it was voted "the best all-time work of American architecture." In 2007, Fallingwater was ranked #29 on the AIA 150 America's Favorite Architecture list. National Register #74001781 (1974)