The whole thing is edible, no fondant (technically edible but I don't count it) and no hidden supports anywhere. The bridge itself is made out of fudge and the rest is chocolate cake and butter cream frosting (the blue is the same as the white: vanilla but with blue food-coloring, the brown is chocolate).
Steps:
1. Make a mold for the fudge bridge
2. Make the fudge and freeze it in the mold
3. Make two cakes, each 13"x9"
4. Make two recopies of vanilla, butter-cream frosting
5. Cut the two cake and mold them so as to be a river, mountains and ridges using the frosting as glue
6. Add the white frosting as a base for the river (it needs a base because of all the crumbs it will develop) and the snow-capped peaks.
7. Turn some of the remaining frosting into blue via food coloring and use that to create the river and feeder streams. Top where appropriate with white for foam caps.
8. Make another recipe of butter-cream frosting plus whatever white frosting is left and make it chocolate.
9. Fill in any unfrosted area (most of the volume will go to the outside edge, most of the work to getting it to meet up on the inside)
10. Cut a space for and add the fudge bridge.
Not bad for someone with no training in this right? After I'd made the fudge and the two cakes it took me a little over two hours to make the frosting and put the whole thing together.
