With the Kartchners on board, Tenen went undercover to research what it would take to develop Xanadu. The Kartchners eventually turned to Arizona's parks department. Even a visit by then-Gov. Bruce Babbitt was shrouded in secrecy. After Arizona purchased the site in 1988 and the secret went public, workers spent 11 years carving tunnels into the limestone and building wheelchair-accessible trails and bridges.
Visitors now glide up to the entrance from the parking lot in electric trams.
Then they stroll into the first of two vaults sealed with giant restaurant-freezer doors. Next, in guided groups of 16, visitors step into the cavern's expansive Rotunda Room. The one-hour tour ends at a small amphitheater on a ridge overlooking Kubla Khan. The grand finale wasn't ready when I was there, but visitors can expect a sound and light show while seated on the concrete benches. Other fossils from the cavern include an ancient horse skull and a bear jaw.