Beneath the Okinawa World theme park in Nanjo, Gyokusendō Cave stretches for about 5 km, though only 890 m is open to visitors along a safe steel walkway. Formed over 300,000 years, this limestone wonder maintains a steady 21°C with high humidity, offering a refreshing contrast to Okinawa’s tropical heat. Stalactites, stalagmites, and delicate mineral curtains glow under soft lighting, while crystal-clear pools like the “Blue Spring” reflect an ethereal blue.

The journey passes through striking formations and into the vast Grand Hall, where towering stalagmites rise like ancient sentinels. Fossilized remains of Ryukyu deer hint at the cave’s prehistoric past, and the sound of dripping water adds to its quiet mystique. Thoughtfully designed paths and railings make the walk comfortable, ending with an escalator that gently carries you back to the surface, like a final reminder you’ve just stepped out of another world.

Formed over 80 million years, Abukuma Cave is a subterranean masterpiece shaped by water and time. The main 600-meter route leads past surreal formations, with an optional 120-meter detour for added adventure. Highlights include the vast Takine Palace, soaring nearly 30 meters high, and the Ryūkyūden (“Dragon Palace”), where towering stalagmites and walls of mineral beads create a natural cathedral.

Along the way, you’ll encounter the Crystal Curtain’s delicate translucence, the towering Christmas Tree stalagmite, and the rare boxwork calcite pattern, unique in Japan for public viewing. The journey ends in Tsuki no Sekai (“Moon World”), where shifting lights mimic sunrise and sunset, transforming the cave into an otherworldly stage. With a constant temperature of 14–15 °C, it offers a refreshing escape in summer and gentle warmth in winter, all while revealing glimpses of life thriving quietly in the underground darkness.

Akiyoshidō Cave, hidden beneath the sweeping karst fields of the Akiyoshidai Plateau, is Japan’s longest limestone cave, stretching over 10 kilometers with about 1 kilometer open to the public. A steady 17 °C year-round makes it a cool summer refuge and a mild winter retreat. Entering through a grand opening, 24 m high and 8 m wide, you’re drawn into vast chambers, some soaring to 80 m in height and 200 m in width. Iconic sights like the 15 m Golden Pillar and the tiered “Hundred Plates” glisten under soft illumination, each formation shaped over countless centuries.

Clear streams wind between stalactites and stalagmites, and for the adventurous, a short guided course offers ladder climbs and narrow passages lit only by flashlight. Around 700 m in, an elevator ascends to the plateau, revealing panoramic views of the Akiyoshidai karst landscape. Here, geology, history, and quiet grandeur merge in a space protected as a Special Natural Monument.

Ryūsendo Cave in Iwaizumi is a national natural monument and one of Japan’s three great limestone caves, stretching over 4,000 meters into the earth. Only about 700 meters are open to visitors, yet within that distance lies a world of luminous underground lakes, stalactites, and timeless stone formations. The “dragon blue” waters of its lakes are so clear you can see nearly 100 meters down, with legends of even deeper unseen pools. In winter, the stillness sharpens their mirror-like surface, creating an almost surreal reflection.

LED lighting reveals intricate rock shapes, including a stalagmite resembling Jizō, the guardian of travelers, dressed with a red bib in quiet reverence. Five bat species roost here, adding to the cave’s living presence. Just outside, the Shin-Ryūsendo Science Museum offers rare insights into the cave’s past, displaying artifacts from the Jōmon period and exploring the deep connection between people and this subterranean wonder.

Hida Great Limestone Cave, perched 900 meters above sea level, is Japan’s highest tourist-accessible limestone cave and a window into a world formed 250 million years ago beneath the sea. About 800 meters of illuminated passages reveal delicate “straw” stalactites, rare gravity-defying helictites, and shimmering underground pools. The journey flows through three themed sections, softly lit “Dragon Palace Nightscape,” the ornate “Dream Palace,” and the stark “Moon World”, before ending at the hidden “Fall of Happiness” waterfall.

A steady 12°C year-round makes it a cool refuge in summer, with safe walkways, railings, and exit points after each section. Above the entrance, the Ohashi Collection Museum displays over 1,000 artifacts, from gold bars tied to a dramatic tale to the founder’s personal treasures. The grounds extend to mountain-view cafés, souvenir shops, and a tranquil trout pond, creating a balance between raw subterranean beauty and peaceful alpine charm.