St. Louis, Missouri's Gateway Arch is another popular American architectural wonder. At 630 ft. from top to bottom, and 630 ft. from base to base this catenary curve impresses millions of visitors anually. The model, though, stands a mere 3'0" tall and contains 3,200 pieces. It look 60 hours to design and 40 hours to build.
Photo of LEGO Architecture exhibit by Wally Bahny for TechRepublic