A bridge is a structure built to span a physical obstacle without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, the material used to make it, and the funds available to build it.

The Rapperswil Seedamm is the artificial causeway at the narrowest area of Lake Zurich between Hurden (SZ) and Rapperswil (SG). The structure contains two bridge segments and is approximately 1 kilometre (0.62 mi) long. The Seedamm carries a road and a railway across the lake, with the railway being used by the S5 and S40 lines of the S-Bahn Zürich and by the Südostbahn Voralpen Express.