Circle

While very few completely spherical buildings exist in this world, the concept of half spherical, or domical building are widely adapted for stadium designs.

There are many benefits of a domical room.
First, the center of a domical building is higher than the outer rim, making ventilation more efficient.
Second, the weight of a domical roof is supportd by its rim, so there is no need for pillars in the middle.

This is especially important for stadiums since there can not be any pillars in a football or baseball field.

Can you find images that help illustrate this concept?