### The Most Visited Islands: O'ahu and Jeju

Island destinations are often celebrated for their unique blend of natural beauty, cultural richness, and recreational opportunities, making them top picks for tourists from around the world. In this context, O'ahu in the United States and Jeju in South Korea epitomize the appeal of island tourism in their respective countries.

#### O'ahu, Hawaii, USA

**Geography and Demographics**
O'ahu, often called "The Gathering Place," is the third-largest of the Hawaiian Islands but the most populous and economically diverse. The island spans about 597 square miles (1,545 square kilometers) and houses over two-thirds of Hawai'i's total population in its capital city of Honolulu. It is characterized by two major mountain ranges—the Wai'anae and Ko'olau—divided by a central plateau.

**Tourism and Attractions**
Tourism is the cornerstone of O'ahu's economy, with the island attracting visitors globally to its famous sites. Honolulu, the state capital, blends the historic charm seen in districts like Chinatown and the modern skyscrapers of downtown districts. Waikiki Beach, arguably O'ahu's most iconic spot, is famed for its golden sands, surf spots, and vibrant nightlife, making it a magnet for international tourists. Beyond Waikiki, attractions like Pearl Harbor, the North Shore known for big wave surfing, and the Polynesian Cultural Center significantly contribute to O'ahu's tourism appeal.

#### Jeju Island, South Korea

**Geography and Demographics**
Jeju Island, also known as Jeju-do, is the largest island off the coast of the Korean Peninsula, and also South Korea’s smallest province. It has an area of about 1,846 sq km (715 sq mi) and a population that hovers around 675,000. The island features a volcanic landscape dominated by Hallasan, the highest mountain in South Korea.

**Tourism and Attractions**
Jeju is renowned for its unique volcanic landscapes, pristine beaches, and cultural festivals, attracting millions of domestic and international tourists yearly. It's especially popular among honeymooners and nature enthusiasts. Key attractions include the Jeju Volcanic Island and Lava Tubes, a UNESCO World Heritage Site, which encompasses Hallasan National Park, the Geomunoreum Lava Tube System, and the Seongsan Ilchulbong Tuff Cone. Additionally, the island offers various outdoor activities like horse riding, hiking, and diving. Jeju's culture, characterized by Haenyeo (female free divers), adds a rich layer of human interest and historical depth to its visitors' experiences.

**Comparative Analysis**
The allure of both O'ahu and Jeju stems from their rich natural environments and cultural offerings. While O'ahu capitalizes on its American ties, surfer culture, and historical sites—including significant events like the attack on Pearl Harbor—Jeju offers a distinctly Asian appeal with its natural scenery, UNESCO recognition, and cultural festivals. This distinguishes their tourism narratives, attracting different tourist demographics reflecting global diversity.

In conclusion, O'ahu and Jeju hold prestigious titles as the most visited islands in their respective countries, owed to their unique landscapes, cultural heritage, and comprehensive tourist facilities. Their ability to draw millions of visitors each year underscores their significance not just as leisure destinations but also as important cultural and economic hallmarks in the USA and South Korea respectively.