Solid structures rely on their own mass and have little internal space, while frame structures are made of connected parts and shell structures have a solid outer surface and hollow interior. Common bridge types include beam bridges which are flat and supported at the ends, arch bridges which use arches to distribute heavy loads, truss bridges made of triangular frames, and suspension bridges with cables anchored at tall towers on each end. Structural components like beams, columns, arches, and trusses are basic building blocks used in a variety of ways to construct strong yet lightweight structures.