Locations for your Lair

"The fake mountain with a hollow interior is yet another site often used by evil geniuses. While on the outside it looks like any other mountain, with the flip of a switch you can transform it into a deadly fortress of doom! Where once stood rock can now stand rocket turrets, as the front opens up to reveal missile launchers and powerful artillery cannons. The central base can easily house your armies of destruction, and the whole thing folds up quite nicely when you are done playing with it. The only caveat with the fake mountain is that you should not place them in the middle of cities. They are for some reason too often noticed there."

The fake mountain has always been a personal favorite of mine, but your own choice of evil headquarters will be a matter of personal taste. Link thanks to John.