Terrain Building: Mycenaean Tholos Tomb
Here's a piece of themed terrain I built for my Mycenaean army, modelled on the tholos tombs the Mycenaeans built. The flat area on top is large enough to hold one base of figures, so this can function as a camp element.
The tomb itself was shaped from styrofoam, then covered in putty filler. The masonry was from a 1/35 diorama kit I bought some years back, and which is still supplying my masonry needs in all sorts of scales - in 15mm, they look like large stones, in 1/72, large bricks. After the filler set, the whole thing was covered in sand, sprayed black, and then dry-brushed in successively lighter shades of brown towards the top.
Here's a link to a wikipedia article about Mycenaean tholos tombs.