A dome is a rounded structure that often resembles the shape of a half-sphere. It is commonly used in architecture for buildings like churches, mosques, and government structures. The design allows for a spacious interior while providing strength and stability. Famous examples include the Pantheon in Rome and the St. Peter's Basilica in Vatican City. Domes can be made from various materials, including concrete, glass, and metal. They are not only functional but also visually striking, often becoming a focal point of the buildings they crown. The use of domes can be traced back to ancient civilizations, showcasing their enduring appeal in design.