Near the end of the movie, when Indy and the gang are on the rope bridge, look at the long shot of the bridge. It's about 60 feet off the ground and is above a rocky bottom. Now look at the shots looking down from the bridge. It appears to be 500 feet off a river!
This was probably an optical illusion which was made to make the scene more intense. A similar scene was done in "Robin Hood Men In Tights" where a bridge was crossing what seemed like a deep canyon with a river at the bottom, but it actually turned out to be a really tiny stream which could be stepped over. The only difference between the two is that this was pointed out in Men In Tights in order to be comical, but it isn't mentioned in the Temple of Doom.
When the Indy films were re-released in 1999 they had an interview with Harrison Ford, George Lucas and Steven Speilberg in which speilberg says 'the ropebridge was not a sfx and that i was afraid to go over it'
That's true- they were afraid, but it showed on the DVD that Ford would run all across the bridge, teasing them lol. As for the bridge and the river, that was a real location.