ˈɜːli tˈʊɹ ɡˈɛsts pˈɜːtʃɪst ðɛɹ tˈɪkɪts æɾə kˈiːɑːsk, bˌʌt ɪn dᵻsˈɛmbɚ tˈuː θˈaʊzənd θɹˈiː ˈeɪ . vˈɪzɪɾɚ sˈɛntɚ wʌz ˈoʊpənd tə ðə pˈʌblɪk.
Early tour guests purchased their tickets at a kiosk, but in December 2003 a . visitor center was opened to the public.