Goofs

As the shipwreck survivors are being brought aboard the Nautilus, the Nanette Newman character is shown wearing no footwear. But in the next shot as they show a crewman carrying her limp body down a corridor on the submarine, she is wearing black boots.

Nemo states his city is 10,000 fathoms deep which is 11.4 miles, the deepest part of any ocean on Earth is just under 7 miles.

Captain Nemo points out a weeverfish and says it is very poisonous and that one scratch from it could be fatal. While a scratch or sting from that fish can be very painful - more than a hornet or wasp sting - there has only been one recorded fatality, and that occurred in 1933 after multiple stings.

Although the movie takes place during the Civil War, Chuck Connors' character talks about growing up in Kansas, which didn't become a state until 1861 at the beginning of the Civil War. However, there was a Kansas Territory, officially from 1854, and he could be referring to the same area by that name.

At the beginning of the movie a ship is supposedly swaying in rough winds, but the bell is not swaying and drops of water are falling down straight.

Despite being 10,000 fathoms deep, in some scenes -- like during the shark battle -- the surface of the ocean is visible just above the action.

Those that escape to the surface at the end of the film show no signs of decompression sickness (aka the bends), even though they come up from 10,000 fathoms deep. In reality they would have died painful, horrible deaths on the way up.