Journey To The Beginning Of Time (1966)

aka: Cesta Do Praveku

Four young boys visit a dinosaur exhibit at the New York City Museum of Natural History. They then row out onto Central Park Lake where they find a secret cave and paddle into a wondrous prehistoric world filled with the very dinosaurs they had just seen. Stars Vladimír Bejval, Petr Herrman, Zdenek Hustak and Josef Lukás.

NOTE: This is the English language version of Cesta Do Praveku (also available here at Rare Movie Collector) which was not released in the U.S. until 1966