Grounds daily 8-8, Apr.-Oct.; 8-6, rest of year. Center open Mon.-Fri. 8:30-4:30, Sat. 9-3. Wilson Hall open daily 8-5; 15th-floor observation level open Mon.-Fri. 8-4:30, Sat.-Sun. 9-3. Art gallery Mon.-Fri. 8-4:30. Guided tours of Wilson Hall are given Wed. at 10:30 and every third Sun. at 1, during the summer. Tours of Lederman Science Center are given the first Sat. of the month at 10. Closed major holidays. Phone ahead to confirm schedule. Allow 2 hours minimum.