Xiaomen Islet, located to the north of Xiyu Township (Yuweng Island), is an independent island covering an area of 0.5121 square kilometers. Known as the "Pearl of the Houchmen Rapids(吼門之珠)," it is famous for its proximity to the turbulent waters of the Houchmen Channel. Xiaomen Islet was connected to Xiyu Township by the Xiaomen Bridge (a bridge spanning the sea), with facilities such as a parking lot and an island-walking path, making it a popular scenic area in Penghu. The name "Xiaomen" (is pronounced like "small door" in Chinese)" originates from a narrow path on the east side of Xiaomen Village, flanked by basalt cliffs. In ancient times, villagers would pass through this path, which from a distance resembled a small door, thus giving the area its name. Xiaomen Islet features typical "square mountain" topography and its unique geological features represent a microcosm of the Penghu landscape. This natural "geographical classroom" combines scenic tourism with outdoor educational opportunities, making it an ideal site for geological exploration.
The Xiaomen Geology Gallery Discovery Hall, established in 2001, boasts an arc-shaped design that incorporates Gaillardia Island's unique stone materials. The building underwent its third renovation in July 2020 and reopened in January 2021, now renamed the "Xiaomen Geology Gallery Discovery Hall." The hall offers immersive audio-visual experiences, transporting visitors back to prehistoric times while showcasing geological wonders. The hall is divided into six main sections: the entrance service area, deep-sea rock area, egg-shaped projection area, dinosaur and plant model landscape area, basalt introduction wall and exit display area. 
Surrounding the hall are rich outdoor geological landscapes, including Whale Cave, a basalt cave shaped like a whale. Legend has it that a giant whale was trapped here, causing the cave's formation. Nearby, there are many uniquely shaped basalt columns and a stone wall garden built from coral limestone, all of which are worth visiting and exploring. 
Recommended Duration of Visit: 1.5 hours

Source: Penghu Travel and Penghu National Scenic Area Administration Court