http://news.nationalpost.com/2012/11/22/above-the-world-in-90-days-china-bui... The original question seems to me very temperature-dependent. --rwg On Sat, Dec 8, 2012 at 10:53 AM, Henry Baker <hbaker1@pipeline.com> wrote: FYI -- "A Lego tower with this many pieces would be approximately 3.5km high" -- i.e., over 10,000' ! This sounds like a challenge to me. I wonder if Lego would provide enough bricks to actually build a 3.5km high Lego tower. The weight per brick is ~2.5 grams. What would the appropriate shape of such a tower be? Perhaps an Eiffel Tower lookalike, only a lot bigger. AnyLatto>If you want to crush a block, all the weight of 10,000 blocks has to be on that single block. So an Eiffel Tower lookalike wouldn't do it, since the weight would be on at least 4 blocks. And I think it would collapse, with the center of the tower crashing down between the four supports, long before it got that big, unless you had something stronger than the normal lego connection holding them together. I suspect even supergluing them together wouldn't be enough. According to the following exchange, Lego bricks cost $0.12, so just a single stack 3.5km high would cost $45,000. In order to build a self-supporting tower, the bricks alone would cost millions of dollars, and the cost of erecting such a structure would also be in the millions of dollars. It would probably make sense to first build a number of identical robots that could put Lego pieces together and then climb up on the growing tower. It might take several years to build it this way, but it would significantly reduce the cost of construction. People don't currently find that the cheapest way to build a skyscraper is to build skyscraper-building robots and have them build the skyscraper. I don't see why the economic equation should change because the skyscraper is built out of legos rather than steel girders. Andy _