Question: Which park, Picos de Europa National Park or Caldera de Taburiente National Park is on an island?
Context: Tobes is one of eight parishes (administrative divisions) in Peñamellera Baja, a municipality within the province and autonomous community of Asturias, in northern Spain.  It is located in the Picos de Europa National Park. Oceño is one of eight parishes (administrative divisions) in Peñamellera Alta, a municipality within the province and autonomous community of Asturias, in northern Spain.  It is located in the Picos de Europa National Park. Lake Ercina is a small highland lake in Asturias, Spain.  It is located in the Picos de Europa, in the Cantabrian Mountains.  Situated next to Lake Enol, together, they forms the group known as Lakes of Covadonga within the Picos de Europa National Park.  Lake Ercina is smaller than Lake Enol.  It is situated at an altitude of 1108 m and its maximum depth is just over 2 m .  The eutrophic lake, covers approximately eight hectares.  Its characteristics are tied to its glacier origin and geographic location. Caldera de Taburiente National Park (Spanish: "Parque Nacional de la Caldera de Taburiente" ) is large geological feature on the island of La Palma, Canary Islands, Spain.  It contains the enormous expanse of the Caldera de Taburiente which dominates the northern part of the island, and was designated as a national park in 1954.  The telescopes of the Roque de los Muchachos Observatory are situated very close to the summit. The Picos de Europa National Park (Spanish: "Parque Nacional de Picos de Europa" ) is a National Park in the Picos de Europa mountain range, in northern Spain.  It is within the boundaries of three autonomous communities, Asturias, Cantabria and Castile and León, which are represented on the body which runs the park. Idafe Rock is a natural stone pillar located in Caldera de Taburiente National Park on the island of La Palma in the Canary Islands. Lake Enol is a small highland lake in the Principality of Asturias, Spain.  It is located in the Picos de Europa Western Massif, Cantabrian Mountains.  It is next to Lake Ercina and together, they form the group known as Lakes of Covadonga, inside the Picos de Europa National Park.  Lake Enol is the larger of the two.  It is situated approximately 10 km from Covadonga and 25 km from Cangas de Onís.  A curving road is available from Arriondas to the lake.  Measuring 0.1 km2 , it is one of the biggest lakes in the area.  Lake Enol is situated 1070 m above sea level, in the Picos de Europa).  It was formed by the withdrawal of a front glacier. The Naranjo de Bulnes (known as Picu Urriellu in Asturian) is a limestone peak dating from the paleozoic era, located in the Macizo Central region of the Picos de Europa, Asturias (Spain).  Its name "Picu Urriellu" is believed to be derived from the term "Los Urrieles" which is used to describe the Macizo Central.  Naranjo de Bulnes is part of the Cabrales region of Asturias, and lies within the Picos de Europa National Park. Trescares is one of eight parishes (administrative divisions) in Peñamellera Alta, a municipality within the province and autonomous community of Asturias, in northern Spain.  It is located in the Picos de Europa National Park. The Lakes of Covadonga (el.  1134 m.) are composed of two glacial lakes located on the region of Asturias, Spain.  These lakes, often also called Lakes of Enol or simply Los Lagos, are Lake Enol and Lake Ercina located in the Picos de Europa range and they are the original center of the Picos de Europa National Park, created in 1918.
Answer: Caldera de Taburiente National Park