The United States is located in the centre of North America and its territory also includes Alaska and Hawaii. As a constitutional federal republic, it is the world's largest economy. It has advanced technology and is a leader in the fields of aerospace and electronics. The United States is a multicultural country, famous for Hollywood films and pop music. Rich in natural scenery, with the Grand Canyon, Statue of Liberty and other well-known landscapes. North America is located in the northern part of the Western Hemisphere, bordered by the Arctic Ocean in the north, the Atlantic Ocean in the east and the Pacific Ocean in the west. The main countries are the United States and Canada. The terrain is varied, with tall mountains in the west, vast plains in the centre and low and gentle highlands in the east. The climate is complex, with both frigid and tropical climates, and is rich in natural resources.