roswell area 51 is the open answer to that supposedly "secret" military base.
People drive through that area and the locals know that the tourists just want a picture of the signs. Its a perfectly harmless tourist activity so the military guards dont even get their panties in a knot. A little park with greys and little green creatures would be better for a photo op. Too bad the Nevadans have not thought of that one at all. The sign would say Welcome to area 51 and a half.