Things to do in Atlanta for Halloween. TLANTA… MEET US UNDERGROUND AFTER DARK. 🩸 This October, something wicked takes over Downtown.Step inside HAUNTED UNDERGROUND — a 21+ Halloween experience filled with haunted spaces, multiple bars, wicked cocktails, live DJs, dancing, and plenty of things that go bump in the night. OCT 1 – NOV 1THURSDAY – SUNDAY21+ ONLY Dress scary. Dress sexy. Dress strange.Just don’t come alone. 👀 Follow @hauntedundergroundatl + @undergroundatlanta for private parties & exclusive event announcements.