The center of Polynesia, the 15 Cook Islands are spread over a vast territory of water. The country is named after Capt. James Cook, the first European explorer to spot Atiu Island. The Cooks have been an independent nation for 26 years though they are a protectorate of New Zealand. Around the island of Rarotonga - the capital - dive sites range from pinnacles and caves to drop-offs and swim-throughs. Aitutaki features a fringing reef with walls, wrecks and caves.