The waterfalls at Cascate delle Marmore are manmade, but you'd never know it. In ancient Roman times, the town of Rieti was plagued by malaria from the nearby wetlands. Roman engineers diverted a river over the cliff to reduce the amount of water in the wetlands, creating a fabulous falls. Over 2000 years, the falls have come to look they belong there, and seeing them is something special. The falls are diverted at points during the day through a plant to generate power, so make sure you check ahead that the falls will be "on". If possible, be at the bottom of the falls (you can walk between the top and the bottom, a shuttle can return you to your starting point) for the turning on of the water. It is a sight not to be missed. The falls are the among the highest in Europe, and watching their racing courses is spectacular. Two final tips: 1) bring a plastic poncho to walk out on the ledge under the falls. It's like a cyclone of water. 2) Eat at the restaurant across the street, Trattoria Trappacchiella. Order the trout. Trout requires cold and rushing water to be delicious and the river Nera has both. Grilled to utter perfection, it is so good my son wanted another for dessert.