The Penghu Great Bridge is 2,494m long. It strides above the Houmen Waterway between Baisha and Siyu Islands. It is said the ocean current underneath the bridge can be as fast as 3m per second—the second most dangerous in Penghu. In particular, when the northeastern monsoon arrives in winter, the ocean current becomes fiercer than ever causing not even a single boat to be able sail on it. Thus, bridge construction work began in 1965 and was completed in 1970 to facilitate marine traffic between the islands. Embankment was expanded in 1984 due to bridge erosion and collapsing. In 1996, the Penghu Great Bridge was re-inaugurated as a duo-pathway bridge. The Penghu Great Bridge looks like a rainbow on the sea. Today, it is not only an important traffic route between Siyu and Baisha, but also a major scenic spot. At the northern tip of the bridge in Siyu some early cement frameworks and some piers of the bridge remain. They respectively show that electricity in the old days was delivered across the seas through high voltage wires across the seas, and that an old bridge existed before the new one was built.Dacang Islet is a great place to appreciate the ocean-crossing bridge.The Dacang Islet, praised as the “pearl of the Penghu Inland Sea,” is located on the inland sea surrounded by Magong, Baisha, and Siyu Islands. The islet also offers a magnificent panoramic view of the Penghu Ocean-Crossing Bridge. Visitors can take a boat from Houkutan, Chongguang Neighborhood, and Magong to the Dacang Islet. In 20 minutes, they will be able to set ashore the place. Dacang is the only islet inhabited by human beings in the inland ocean of Penghu. The name “Dacang” may have derived from the fact that the inland sea is a major fishing ground in Penghu. Along the Dacang Islet, the shores are smooth, and tidal flats are vast. It is especially featured by five giant tidal weirs.