Japan is a country full of crazy ideas, but their plan for the world's tallest building makes every single one of their insane USB devices look downright reasonable in comparison. It's a 13,123-foot-tall superstructure. To give you an idea of just how tall that is, it's about 7 times taller than the current tallest building on earth, and it's a solid 700 feet taller than Mt. Fuji. Yeah, it's pretty tall.

The mountain-shaped building, known as the X-Seed 4000, would be able to house upwards of 1,000,000 people and would cost somewhere between $300 billion and $900 billion to construct. Due to the size, scope, and, well, general insanity of the project, the chances of it actually being built are somewhere between slim and none. But hey, it's nice to know that at least one country out there is willing to make plans for stuff this crazy. Keep on keepin' on, Japan. — Adam Frucci

Inhabitat, via Geekologie