Constructed in 1978, High Island Reservoir is formed by connecting Sai Kung Peninsula with High Island by the east and west dams that enclosed Kwun Mun Channel. The reservoir has the largest capacity among all other reservoirs in the territory. Yet what steals the limelight is Biu Tsim Kok, a semi-circular cape on the north side of the East Dam. The hexagonal rock columns surrounding it give the geological landform a picturesque beauty, making it a popular social media check-in spot among hikers. Biu Tsim Kok overlooks the entire East Dam and looks out on Long Ke Wan and Tsang Pang Kok Tsui in the distance. It is also one of the few places that offer an aerial view of the hexagonal rock columns.