10 feet 4 inches

My eleven year old son, Ryan, after helping me on the other towers decided to do one himself. This one is 10 feet 4 inches tall and is a very elegent design. The tower is the same from base to top and is a simple lego square cylinder using six 2x4 bricks per layer (every other layer was made of two 1x4 bricks next to each other). The tower has 326 layers using about 3000 pieces and weighs about 12 pounds. The base is solid bricks and is seven layers tall with each layer just bigger than the layer above.

Even though the tower is very slender the solidness of this cylinder design cannot be denied. I am thinking that perhaps taller towers could be made of four of these towers as the corner pillars with each connected every few feet by big square frames. That would make it balance much better at tall heights. One possible drawback of the design is that if it collapses the falling pieces could be quite large and heavy.