Beitanzhu Island Introduction
Penghu has two islets named Tiezhun Island, which are named for their resemblance to an anvil. The northern Tiezhun Island, belonging to Baisha Township, is located offshore to the northwest of Penghu Island. It is an uninhabited island primarily composed of basalt plateaus and surrounded by steep sea cliffs. The bottom layer consists of columnar basalt and volcanic breccia, which are relatively fragile rocks. Due to the influence of the northeast monsoon, the northern coast has been eroded by ocean currents for a long time, forming a huge sea cave that even small boats can enter. This sea cave is larger than the Blue Cave of Xijij Island and is the largest sea cave in Penghu. Inside the cave, as it does not receive sunlight, the temperature is three to five degrees lower than outside, earning it the nickname "Air Conditioning Cave." Once on the island, one can see not only the plateau-like basalt formations but also uniquely shaped honeycomb rocks and the basalt joint grooves formed by water erosion, which are characteristic of the terrain of northern Tiezhun Island. It has also served as a military target range, leaving behind many iron fragments and rock debris. Due to the short and shallow intertidal zone of northern Tiezhun Island and the lack of surrounding platforms, there are almost no visitors, leading to the gathering of thousands of birds for nesting, the most numerous being the white-faced storm petrels. Whenever a boat approaches, the white-faced storm petrels sound alarms and circle in groups overhead, seemingly reminding tourists that they are the real owners of this place!
