Free. Under 18 are not permitted on Tues. or on Site 300 tours.
Center open Tues.-Fri. 1-4. Guided tours of the main site are given Tues. at 8:30 a.m. Site 300 tours are given by appointment when staff is available. Tour reservations must be made at least 2 weeks in advance and are subject to availability. Closed major holidays. Allow 30 minutes minimum.