32 Abandoned Cities That Are Slowly Being Reclaimed by Nature

19. Gunkanjima, Japan – The Concrete Island Devoured by the Sea

In the middle of the sea, off the coast of Nagasaki, a small island looms like a ghost ship—an eerie, crumbling mass of concrete known as Gunkanjima (or "Battleship Island"). Its real name, Hashima Island, is barely remembered; instead, it’s known for its haunting, post-apocalyptic appearance—a once-thriving mining community now left at the mercy of the elements. In the late 19th century, the island became a hub for coal mining, its rich underwater reserves fueling Japan’s industrial expansion. To accommodate the thousands of workers who flocked there, Mitsubishi built some of Japan’s first concrete high-rise apartments, cramming over 5,000 people into the island’s tiny, 16-acre expanse. At its peak, Gunkanjima was the most densely populated place on Earth. Then, in 1974, the coal mines shut down, and within weeks, the island was completely abandoned. With no one left to maintain the structures, Gunkanjima became a crumbling wasteland. For decades, Gunkanjima was off-limits, its decaying structures too dangerous to enter. But in recent years, limited tours have allowed visitors to glimpse this hauntingly preserved fragment of the past. It has even been featured in films, most notably as a villain’s lair in Skyfall, the James Bond film.