Accompanied by his American backer David Innes (Doug McClure), Victorian inventor Abner Perry (Peter Cushing) gave a shakedown test to his marvelous earth-boring craft. Unfortunately, the ship punched through to the world's center, where they stumbled upon a culture of humans in thrall to a race of prehistoric bird creatures. Effects-filled take on the Edgar Rice Burroughs tale co-stars Caroline Munro, Cy Grant, Godfrey James. 89 min. Widescreen; Soundtrack: English DTS HD mono Master Audio; interviews; audio commentary; theatrical trailer.