Hawaii, a U.S. state, is an isolated volcanic archipelago in the central Pacific. Its islands are famous for their rugged landscapes of cliffs, waterfalls, tropical foliage and beaches with golden, red, black and even green sands. Of the 6 main islands, Oahu has the capital and Hawaii's largest city, Honolulu, home to Waikiki Half-Moon Beach and World War II memorials at Pearl Harbor.