Looks like a particularly big site has been uncovered;from the article:
The article is here. Personally I'd love to have a look see.
The vast weapons facility was uncovered last week near the town of St. Georgen an der Gusen by a team led by Austrian documentary- maker Andreas Sulzer, who said it was “likely the biggest secret weapons production facility of the Third Reich.†The 75-acre industrial complex is located close to a second subterranean factory, the B8 Bergkristall facility where the Messerschmitt Me 262, the world’s first operational jet-powered fighter, was produced toward the end of World War II
The article is here. Personally I'd love to have a look see.