16. Guaira Falls

For any tourists chasing waterfalls, Guaira Falls was once an incredible option. Situated on the border of Paraguay and Brazil, the breathtaking waterfalls were among the strongest on earth. They pushed out an estimated 13 million gallons of water every second and could reportedly be heard from 20 miles away, or so we hear.

That all changed in 1982, when suddenly the waterfall dried up. It seems that even the strongest cascades were no match for man-made construction because the newly-constructed Itaipu Dam blocked off the falls’ water source. Although readily visible, the falls technically exist somewhere, if you can find them under a massive lake.