Underground Japan 日本の地下

Underground maze

Japan is known for the diversity of its landscapes and panoramas that charm tourists across the country. But it also has a lot to offer in its basements... A closer look at some of "little-known Japan".

The Seikan Tunnel


The Seikan tunnel, 53.85 kilometers long, is the second-longest tunnel in the world after the Gotthard tunnel. It connects Aomori, north of Honshû, to the island of Hokkaidô, under the Tsugaru Strait, and required more than 10 years of drilling work (24 years of work in total). The lowest point of the tunnel is 240 meters under the sea. To visit this technical feat, you can buy a ticket for 1300 yen (about$11/10€) at the Seikan Tunnel Museum, giving you access to both the museum and a train ride in the tunnel. Note that access to the tunnel is closed between December 1 and March 31.

Seikan Tunnel


Akiyoshido Limestone Cave


Akiyoshido Cave is located in Yamaguchi Prefecture, under the Akiyoshidai Quasi-National Park. The limestone cave, over 300 million years old, stretches over 10 kilometers and has ceilings that can rise to 80 meters. You will be able to stroll under ochre-colored stalactites and admire the mineral formations that rise in stairs along the path. One kilometer is open to tourists strolling, time to admire the mineral diversity of this underground giant.

Read also: The three little-known caves of Mount Fuji

Akiyoshido Cave

Okayama Prefectural Tourism Guide

Gyokusendo Cave


After Akiyoshido Cave, you can descend into another Japanese subterranean wonder, in Okinawa Prefecture. 300,000 years old, 5 kilometers long, it was only discovered in 1967. The 890-meter route takes you past masterpieces of nature such as the "blue fountain" where water carried by azure backgrounds rises above several natural basins. The ceiling of the spears is particularly impressive, the stalactites being so close together and parallel to each other that they give the image of arrows ready to be fired.

Gyokusendo Cellar

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The G-Cans


The G-Cans is an "outer metropolitan area" flood tunnel in Saitama Prefecture. It took 14 years to build and commission these 5 concrete silos, 65 meters high, connected by more than 6 kilometers of the tunnel. The water reservoir is 177 meters long, 78 meters wide, and has a height of 25 meters. With its 59 pillars, it looks like an underground temple and has already been the subject of several television productions.

Read also: Iwami Ginzan

G-Cans tank


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