Just when you thought there couldn’t be any more really interesting buried places, Don Wildman is back sinking to new depths. (Sorry, I couldn’t resist). The 11 episodes of season two find Wildman returning to Germany, this time to explore Berlin’s hundreds of World War II bunkers. In New York, it’s secret societies, not unlike his trip to Boston in season one. It’s amazing what’s down there. Wildman also checks out Soviet bases, Mayan ruins and Washington, D.C. Does he find Dick Cheney’s bat cave? No, but he does gain access to all sorts of underground super-bunkers and high-tech control centers. We even get a glimpse of the secret location under a Virginia resort, where members of Congress and the White House would have gone in case of a nuclear attack. National treasure, indeed. Grade A-