The Bunaken National Marine Park was formally established in 1991 and is among the first of Indonesia's growing system of marine parks. The park covers a total surface area of 89,065 hectares, 97% of which is overlain by sparkling clear, warm tropical water. The remaining 3% of the park is terrestrial, including the five islands of Bunaken, Manado Tua, Mantehage, Nain and Siladen. Although each of these islands has a special character, it is the aquatic ecosystem that attracts most naturalists.