A dome is a hemispherical roof that encloses a space without internal supports. It is one of the most efficient structural forms in architecture. A dome carries loads in compression, spreading them evenly around its base. That is why ancient builders could span vast spaces with stone and brick long before steel existed.

The Pantheon in Rome, completed around 126 AD, remains the largest unreinforced concrete dome in the world. Its coffered interior and central oculus have inspired architects for centuries. Later domes — Hagia Sophia, the Florence Cathedral, St. Peter's Basilica, the U.S. Capitol — pushed the form further.

Modern domes use steel, reinforced concrete, and even inflated fabric. Geodesic domes, popularized by Buckminster Fuller, distribute forces through a network of triangles. They are lightweight and strong, though they can be difficult to weatherproof.

Domes are not just roofs. They create interior volume that feels sacred, civic, or simply grand. The shape itself carries meaning.