This fabulous building is one of the most beautiful and unique in the world. There are no visible supports to its distinguished dome roof. This was accomplished by piling dirt inside the upright structural steel for the walls, forming the shape of the roof, then reinforcing steel laid and concrete poured. When this was cured, the dirt was taken out, and there was the solid steel and concrete dome. Albuquerque Municipal Airport Albuquerque, New Mexico.