I've made some wide river sections and a wooden bridge to cross them. The bridge is made from thin wood and sections of those small, square-section bamboo skewers with handles on the end.

The other recent civil engineering project was a tired, old rope bridge between two crags.

The structure is made from scraps of card on a length of chicken-wire! A couple of rare earth magnets hold it in place. The dhows were built using the plans available from General Tremorden Redderring's Colonial warfare page. The longboats are made from card and foamcore.
More toys as I get them built and photographed.