Sanxiantai is a former isthmus — now islet — located on Taiwan's southeast coast, just north of Changbin. People are drawn here to admire the arresting sight of the eight-arched bridge that connects the coast to the islet, and most never go much further than the mainland-side end of the bridge. However, if you push on a little further, the islet has much to explore, including sea caves, snakes, and fossilised corals.