Trying to figure out what movie this is?

This movie is old but not super old i think....cause i remember seeing
it when i was younger and I'm 15 right now. i don't remember the name
i just remember bits and pieces.
okay so what i remember is this: i remember I'm not sure if kids or
adults but people traveling or something to some place...and then
these people get to this place....i know thats very vague....but then
i remember people going in a submarine or something under water? and
then there must have been a hole in the submarine? or something and
then i remember so many crystals.
and i don't know why i know this isn't the name of the
movie..................but this word always comes to me when i think
about this movie "ethiopia"....i really really need to know the name
of this movie...