Beitenshan Island Introduction
Penghu has two islets named Tiezhin (Iron Anvil Islets), which are named for their resemblance to an anvil. The northern Tiezhin Islet, part of Baisha Township, is located off the northwest coast of Penghu Island and is an uninhabited island primarily composed of basaltic plateau. Surrounded by steep sea cliffs, the lower layers of columnar basalt exhibit volcanic breccia that is relatively fragile. Due to the influence of the northeast monsoon, the northern shore has been eroded by sea currents over time, forming a large sea cave that even small boats can enter. This cave is bigger than the Blue Cave at Xiji Islet and is the largest sea cave in Penghu. Inside the cave, sunlight cannot reach, making the temperature 3 to 5 degrees lower than outside, which is why it is also referred to as the "Air Conditioned Cave." Upon reaching the island, one can see not only the platform-like basalt but also uniquely shaped honeycomb rocks and basalt joint grooves formed by water erosion, all characteristic of the northern Tiezhin Islet's terrain. This area was once used as a military firing range, leaving behind numerous iron pieces and rock fragments. Additionally, due to the shallow intertidal zone and the lack of nearby platforms, very few people visit the northern Tiezhin Islet, making it a breeding and resting ground for thousands of birds, particularly the white-browed tern. Whenever a boat approaches, the white-browed tern emits warning calls and circles in groups above, as if reminding visitors that they are the true owners of this place!
