This is not my idea; I saw someone else's project online a while back, and ever since I've been looking for an opportunity to try it. Then I was with a friend recently who was punching out the counters for his newly purchased copy of the Congo ruleset, and I asked if I could have the remaining cardboard frame left after all the counters are punched out.
I then cut the frames into sections to look like partially destroyed walls, and glued them on to 6" x 6" cork bases. Next, I'll be adding some detail bits, an then spraying on a base coat.