Si Phan Don, also known as the "Four Thousand Islands," is a picturesque archipelago located in the Mekong River in southern Laos. This region is famous for its stunning natural beauty, featuring lush landscapes, waterfalls, and a variety of islands, some of which are inhabited. Visitors can enjoy activities like cycling, kayaking, and exploring local villages. The largest island, Don Khon, is known for its historical significance and the Khon Phapheng Falls, one of the largest waterfalls in Southeast Asia. Si Phan Don is also a habitat for the endangered Irrawaddy dolphin, making it a unique destination for nature lovers and eco-tourists.