Pulau Weh (or We) is a small volcanic island located in the northwestern island of Sumatra. This island was once connected to the island of Sumatra, but then separated by the sea after the last volcano eruption in the Pleistocene. The island is located in the Andaman Sea. The largest city on Weh Island, Sabang, is the westernmost city in Indonesia. The island is famous for its ecosystem. The Government of Indonesia has established a territory as far as 60 km² from the edge of the island both in and out as a nature reserve. Large mouthed sharks can be found on the beaches of this island. In addition, this island is the only habitat for frogs whose status is threatened, Bufo valhallae (genus Bufo). Coral reefs around the island are known as the habitat of various species of fish.