From Wikipeda:- "The Mathematical Bridge is the popular name of a wooden bridge across the River Cam, between two parts of Queens' College, Cambridge.
The bridge was designed by William Etheridge, and built by James Essex in 1749. It has been rebuilt on two occasions — 1867 and 1902 — but has kept the same overall design."
For more information on the Mathematical Bridge, checkout this Bridge Blog.
Photo replaced 28/10/06.