A puzzle of totally different dimensions, the London Tower Bridge is a remarkable model of the famed 19th-century bridge over the Thames River. The vividly detailed pieces are made of quarter-inch-thick foam with illustrations in paper on the face sides. Spanning 42 inches once completed, this puzzle is a challenge for the adept puzzler with 819 pieces. The instructions offer tips on organizing the work and attaching the decorative pieces to the finished work. However, puzzlers will need to think architecturally to create this towering achievement. --Lynne Sampson