Here's another project from a few years ago using recycled materials (I'm a big fan of recycled projects as you may have gathered...)
This group of grade 2s and I collected loads of old cardboard boxes, cylinders and newspapers to construct these fantasy castles. We looked at pictures of real castles in the U.K and Europe as well as drawings in fairy tales so they could get ideas about the important features of castles.
Then there was cutting, gluing and taping together of bits and pieces before papier mache with newspaper and a coat of paint. I like that they are imperfect - almost like old castles in ruins.