Located about 29 kilometers along the No. 2 Provincial Highway is Shimen (Stone) Arch. This is not a cave at all, but a stone arch formed by erosion. Standing at the side of the highway, it offers an excellent spot to look out at the sea. On top of the stone arch there are seats and what remains of a gun emplacement. It is the perfect place to enjoy the sunset or watch the clouds that hang over the vast northern ocean. The arch was formed by tidal erosion before the land was pushed upward. It now stands high and dry overlooking the coast. As the whole structure is now above ground, it is an ideal showcase for the different geological strata in this part of Taiwan.source: Tourism Bureau, Ministry of Transportasion and Communication