What is the tallest a building can be?

Answer 1

The limits of architecture really depend upon the engineering techniques that are used. For all normal purposes, you can't go beyond a certain height because the air gets thinner the higher you get, and at some point, perhaps a mile up, it gets too hard to breathe. But then, you could in theory have an air-tight building with its own internal air pressure, like a spaceship. Then we have the problem that the taller a building is, the more likely it is to fall over. But you could stabilize an extremely tall building by connecting it by cables to an asteroid in orbit around the Earth (after first collecting the asteroid and putting it in orbit). Such a building could in theory be thousands of miles high. Whether it would actually be worthwhile to build such a building is another question. But it is hard to be sure in what direction human civilization may evolve in the future.