Well, you didn't say "rope & wood bridge" now, did you?!?! You might find some help on rope & plank/slat suspension bridges at these sites:http://www.machovec.com/rope/bridges.htmhttp://www.homeschoolblogger.com/grelihm/268470/(It's a LOT harder to find info on these kind of bridges it seems! One frustrated guy looking for plans/help wrote: "Come on! It can't be that hard! I mean people in third-world countries build them every day!" )