Having been a base for the Army 101st Amphibious Reconnaissance Battalion, and at the end of a winding and circuitous route, the Yanxiu (""swallow's nest"") Tidal Cave is a coastal tunnel. It is linked via an underground passageway to the open sea, and when the tide comes in or goes out, the sound of the water as it rushes out through the passageway to the sea fills the cave. The sound of the waves is pleasant, and whiling away time here listening to Nature brings calm to both mind and soul.