Why is the Pentagon five-sided?
- With its pentagonal ground-plan, the Pentagon resembles a fortress. It was built from 1941 to 1943 in Virginia, according to the plans of the architect George Bergstrom.
- The building was supposed to symbolize strength and unity, and army, Navy and air force clubs. Disposed of the building by the then President Franklin D. Roosevelt.
- Inside should be on four floors of space for 40,000 people. In addition, a requirement was that as little as possible steel is installed.
- The pentagonal shape of the Pentagon makes that possible. Despite the size of the building can be any point within seven minutes.
- Today, about 23,000 people work on the 6.4-million-square meters. Still, the Pentagon is the largest Low-Office-office building in the world.

Why is the Pentagon five-sided?
It's still much more efficient: mathematicians have the perfect Pentagon shape found.
