Mudou Islet () is situated at the north end of the Penghu islands, only 7 km away from Jibei islet to the south; the island is 454 metres in perimeter and only 0.021 square kilometres in area, it is a tiny islet, famous for its Mudou Lighthouse. The waters between Mudou islet and Jibei islet consist of a deep water abrasion platform, and submerged reefs can be found everywhere in the area, hence, the numerous accounts of shipwrecks. It is said that ancestors who lived on Jibei used to pick up floating stuff from the wrecked ships. But for precisely the same reason, animals and plants under the sea can all enjoy sufficient sunlight, and people above water can also see right to the bottom of the ocean. To ensure the safety of the boats while travelling the dangerous area, the lighthouse was built on Mudou in 1921, when Taiwan was a Japanese colony. An iron-framed lighthouse of 40 metres high, painted in black and white stripes, standing as the tallest lighthouse in East Asia.