When Eleanor Roosevelt first laid eyes on Iguazu Falls she said, "Poor Niagara". I've never been to Niagara Falls (or Iguazu Falls), but from my limited experience visiting waterfalls (the most impressive being Akaka Falls in Hawaii), I can say that even just one waterfall that is 100 feet high is an amazing sight to behold.
Iguazu Falls is an impressive series of waterfalls that spreads across both Brazil and Argentina. I can't imagine the feeling of being at Iguazu Falls, with thousands of feet of water crashing down at heights of up to 270 feet. Scary. Amazing. Breathtaking. Wild. I don't know what I'd call it, but I'm pretty sure it's pretty inspiring.