Yuma, Arizona
Yuma, Arizona gets the most sun exposure per year of any place on earth, with about 11 hours of sun per day, which works out to about 4,015 hours of sun per year. Yuma is a dry, desert landscape, which is the environment most associated with large amounts of sun exposure.
Phoenix, Arizona
The next sunniest place on earth is also located in the United States, and even the same state as Yuma. Phoenix gets somewhere around 10.6 hours of sun per day, which averages out to something like 3,872 hours of sun per year. Phoenix is located only about 180 miles from Yuma, and is a very similar ecosystem, owing again to the large amounts of sun exposure experienced throughout the year.
Aswan, Egypt
The third sunniest place on earth is not in the United States, but in another country that is associated with a lot of sun, which is Egypt. Aswan is located in the south-east of Egypt, on the eastern bank of the Nile river. It gets about 3863 hours of sunlight per year. Despite being such a sunny place, where solar panels would be an ideal form of power generation, Aswan is actually known for several dams that generate large amounts of hydroelectric power.
Las Vegas, Nevada
The fourth sunniest place in the world, and fourth best place to build a solar power installation, is also in the United States, but not in Arizona. Las Vegas gets about 10.5 hours of sun per day, or 3,825 hours of sun per year, which means it loses out to Aswan, and a United States clean sweep of the top three spots, by only 38 hours of sun per year.