ObscureHollywood.net’s review published on Letterboxd :
Professor James Mason, a geologist; his student Pat Boone; Arlene Dahl, the widow of a rival geologist; and athletic Icelander Peter Ronson journey under the earth toward its core, following in the footsteps of an explorer who made the trek 300 years previously. The group passes through many perils and eventually reach an inland sea at the center of the earth. After successfully crossing the sea, they find the sunken city of Atlantis. The exit from the depths is up the chimney-like core of the volcano that had destroyed the city. The eruption of the volcano carries them, in an ancient alter stone, back to the surface.
A fun and adventurous movie with lots of incidents that imperil the explorers and absorb the attention of the audience. The movie is based on a Jules Verne novel.