20. Cascata Delle Marmore, Italy
The Cascata delle Marmore (Marmore’s Falls) is a man-made waterfall created by the ancient Romans. Its total height is 165 m (541 feet), making it the tallest man-made waterfall in the world. Of its 3 sections, the top one is the tallest, at 83 m (272 feet).
It is located 7.7 km from Terni, a provincial capital of the Italian region of Umbria.