Journey behind the falls is literally what it says and you get to this via Table Rock. When we were there the main viewing platform still had ice on it so we were not allowed to go there, but it meant that we only paid a couple of dollars each.
You get in an elevator to travel down to below falls level. When you exit you can either go straight to the viewing area or go down the tunnel and look through the windows directly behind the falls. The tunnel is quite long and there are several viewing windows. The view is rather unimpressive as you are literally looking from directly behind the falls and really cannot see anything other than a hole with water pouring past it, but it is the noise that really impresses. It is incredibly loud and you really get a sense of the power of the water.
After the viewing windows, you can then go to the upper viewing platform, the only one we could see at the time. You are located to the side and under the falls and the water gushes past you just a couple of feet away. You get very wet, so watch your camera!
The other viewing area, as I said, was still icebound when we visited so we could not enter; however, if you do you see the same view, but from outside, so get much wetter.
As this tour costs only a few dollars, it is worth doing; after all, where else could you stand behind such a huge waterfall?
The main thing I will take away from this tour is the noise -- awesome.