Tomogashima

Tomogashima is a group of small uninhabited islands floating in the Kitan Strait between Wakayama and Awaji Island; the main one, Okinoshima, is the one visitors explore. From the Meiji era through World War II the islands were a restricted military zone guarding the approach to Osaka Bay, studded with coastal gun batteries, ammunition stores, and brick tunnels. Abandoned and left to the forest for decades, these red-brick ruins are now draped in moss and creeping vines, and their dreamlike, half-reclaimed look has made the island hugely popular as a real-world version of the floating fortress from Studio Ghibli's *Castle in the Sky* (Laputa) — though the resemblance is unofficial. The undisputed highlight is the No. 3 Battery ruin, a sunken brick complex where you can wander the arched magazine rooms and underground passages (a flashlight helps in the dark sections). A well-marked loop links the No. 2 Battery, a hilltop observation deck with views across the strait, the No. 3 Battery, and a striking white Western-style lighthouse standing over the cobalt sea; walking the popular circuit takes about 2.5 hours, and seeing the whole island comfortably takes 3–4 hours. Getting there is part of the adventure: a train to Kada, a walk to the port, and a short ferry across. Bring water, snacks, and proper shoes — the island has only minimal facilities, the trails are unpaved and hilly, and you must catch the last ferry back.