Police in Paris discovered a fully equipped movie theater in a large and previously uncharted part of Les Catacombes, underneath the 16th arondissement. A smaller cave next door had been turned into a restaurant and bar.

When police returned a few days later, the secret theater’s power and phone lines had been cut and a note was left on the floor: “Do not,” it said, “try to find us.”

How freaking cool is that?