Tours are given Mon.-Fri. at 11 (also Wed. at 7 p.m.), Sun. at 10:30, Apr.-Sept. Rooftop tours are given Mon.-Fri. at 10 (also Sun. at 10:30 or 11:30; phone for schedule), Apr.-Sept. Weekday morning tours depart from the southeast lobby. Wed. evening tour departs outside the south door. Sun. morning tour begins at the east gate. Rooftop tours begin in the lobby at door 15 (Mon.-Fri.) and at door 20 on Sun. Closed major holidays. Phone ahead to confirm schedule. Allow 1 hour minimum.