The X-Seed 4000 is the tallest building ever fully envisioned. Its proposed 4-kilometre (2.5 mi) height, 6-kilometre (3.7 mi) wide sea-base, and 800-floor capacity could accommodate 500,000 to 1,000,000 inhabitants. This structure would be composed of over 3,000,000 tons of reinforced steel.

It was designed for Tokyo, Japan by the Taisei Corporation in 1995 as a futuristic environment combining ultra-modern living and interaction with nature. Methods of transportation within the X-seed would most likely include MagLev trains.

The X-Seed 4000 "is never meant to be built," says Georges Binder, managing director of Buildings & Data, a firm which compiles data banks on buildings worldwide. "The purpose of the plan was to earn some recognition for the firm, and it worked."

Some estimate that the cost to construct the X-Seed 4000 structure may be somewhere between US$300–900 billion, in 2006 dollars ($585 billion–$1.05 trillion in 2015).

This model is also perfect for steampunk, sci-fi, or any other scenes needing a futuristic-looking building.

Product Features:- Approx 100,028 polygons.- Made entirely with 3 point polygons (triangles).- Does not include any grouping information or parts.- This version includes an mtl file, which your software program should read to colorize the model.- The model has basic UV mapping and textures (in jpg format) are included, at 2048x2048 pixels.