When did waterfalls first appear?

What is the river that forms the eastern border of the state of Vermont? When is it flood season in Egypt? Does water move into river basins from areas called watersheds? What is a lake bed? Warm ocean water is carried throughout the northern Atlantic Ocean through currents called the? Why would Thailand tropical rain forest be a good place to make a nature film? What country has many tropical forests where toucans and other tropical birds live? What are the food chains of the Nile river? When was the Acropolis made? What is the least busiest day at Universal Studios Orlando? When is it most likely for a river to become a stagnant? How much are Busch Garden tickets in Williamsburg Va? Is there any unusual animals in Europe? Is a Fountain a body of water? What is the country located at the northern end of the Persian Gulf? What was the scandal of kathryn howard? Was a medal ever awarded for service in the Gulf of Aden or Persian Gulf when the Hostages were taken in Iran in 1979? In the late nineteenth century the british commonly referred to the suez canal in egypt as lifeline of the empire because it? How fast does fresh does fresh water freeze? Who made Versailles?