1 Adam: Within the plain is a mountain carven by the god Poseidon into a palace, ringed by three concentric moats.
2 Adam: The Atlanteans used this as the core of their capital city.
3 Adam: The city walls are gilded with orichalcum. Getting some for this model cost a pretty penny, let me tell you.
4 Jamie: Don't you think you're going a bit overboard with this Atlantis model?
4 Adam: We can't stop now! It's a sunk cost!

I'm not sure where'd you go to buy orichalcum these days, but obviously the Mythbusters have some good suppliers for all the materials they need. I am sure it'd be very expensive though, as it's in the same sort of class of metals as gold and silver and platinum.