"Niagara of the West"
Shoshone Falls is a stunning waterfall on the Snake River near the town of Twin Falls, Idaho. The falls are over 200ft. high (higher than Niagara, mind you) and are really one of the great natural wonders in the west. If you can, try to visit Shoshone Falls in the late spring when all the melting snow guarantees the falls will be roaring with water. Once you get to the park, it costs $3 to enter (really, it's a parking fee) and then you have a couple of observation areas, a snack bar, and a grassy area where you can lay out or go for a swim in the lake. I'd suggest taking one of the trails that leave from the parking lot. Each trail doesn't take more than an hour and a half at most and they pass by several view points which are arguably better than the main one at the entrance.