Turner Classic Movies ran the 1961 and the 1929 versions of Mysterious Island, both based on the Jules Verne book, a book I have not read. Actually the 29 version is The Mysterious Island and the 1961 version is The less. I had seen the 1961 version once in 1990 but I didn't remember anything of it. I didn't even remember the Ray Harryhausen giant bitey, pinchy critters. It just didn't look familiar. The 61 version has some civil war era guys in a hot air balloon who land on this island and guard some women from giant creatures until the pirates come. Then it gets interesting. Only after something mysterious sinks the pirate ship does Captain Nemo reveal himself. Then there's a volcano. Holy hot lava. Luckily some people escape death. Because it's of the time and with some production help this movie tries to make the visual connection to the Disney 20,000 Leagues Under The Sea. The Nautalis is very similar inside and out. Herbert Lom is very like James Mason when playing Nemo. It's a slow movin' movie with some nice score.
I am pretty sure I hadn't seen the 1929 version. Here's the plot summary from the IMDb.
On a volcanic island near the kingdom of Hetvia rules Count Dakkar, a benevolent leader and scientist who has eliminated class distinction among the island's inhabitants. Dakkar, his daughter Sonia and her fiance, engineer Nicolai Roget have designed a submarine which Roget pilots on its initial voyage just before the island is overrun by Baron Falon, despotic ruler of Hetvia. Falon sets out after Roget in a second submarine and the two craft, diving to the ocean's floor, discover a strange land populated by dragons, giant squid and an eerie undiscovered humanoid race.
There are a few good comments here. The silent/sound version is a wonderfully goofy film at times. Especially the underwater village. The undersea people were great, running away from the giant sea monster, which looked like a baby aligator with a spine pasted to it. Both of these films were interesting enough to watch but I don't think I'll go out and replace them with store boughts.