Oahu ranks as the most bustling and developed of all the islands. Tourists flood the area for its abundance of lodging and shopping venues, and for its waterfront activities. Oahu is also home to the state's most popular tourist attraction, Pearl Harbor's USS Arizona Memorial, and to Iolani Royal Palace. Most of the island's activity is concentrated in Honolulu and Waikiki, on the south shore. But venture north and you'll find impossibly blue bays, surf-slapped beaches and verdant valleys.