Journey to the Center of the Earth (ep04) The Central Sea 63/07/02

This was an old-time radio serial based on the Jules Verne classic of
the same name, that was broadcast on the BBC Radio in 1963.
The adventures of Professor Von Hardwigg, his nephew Harry and their guide,
Hans are told as they go through a volcanic tube in Iceland. As they
reach the center of the earth, they encounter prehistoric animals and
other hazards.
There have been films, cartoons, amusement park rides,
video games and even a musical album, adapted from this famous novel.