The facility was specifically designed with 'explosion-proof' architecture, featuring thick reinforced concrete walls intended to vent potential blasts upward rather than outward.
The tunnels were carved directly into the basaltic terrain typical of Penghu's volcanic geology.
During the Japanese occupation, this site acted as the primary logistics hub for the Mako Guard District's ammunition supply.
The interior temperature remains significantly lower than ambient external temperatures year-round due to the thick concrete and subterranean positioning.
The Xiyu Ammunition Depot Military Cultural Park, often called the Copper Wall and Iron Bastion, is a preserved underground military bunker complex located on the Penghu archipelago. Originally constructed during the Japanese colonial period, the site served as a strategic ammunition storage facility for the Imperial Japanese Navy. The complex is engineered with massive concrete walls and reinforced iron doors designed to withstand heavy bombardment and prevent chain-reaction explosions. Visitors traverse a series of interconnected tunnels and chambers that maintain a naturally cool climate. The site provides a rare look into the logistical operations and defensive architecture utilized during the Pacific War. It currently functions as a military history museum showcasing refurbished internal spaces and historical documentation.
The heavy, reinforced iron entry doors that give the site its 'Copper Wall and Iron Bastion' nickname.
Bring a light jacket as the underground tunnels are consistently cold.
Wear sturdy, closed-toe walking shoes to navigate the slightly uneven concrete flooring.
Utilize the provided informational placards to understand the historical context of each specific chamber.
Do not attempt to enter areas cordoned off by safety ropes, as some structural parts of the tunnels are prone to high humidity and slippage.
Closed on Wednesdays.
Maintain a respectful tone as this is a former military installation; do not touch the preserved historical artifacts.
