Gunkanjima

Hashima is a rock about 480 metres long that was built up with reclaimed ground around an undersea coal seam and enclosed in a sea wall, which gives it the profile that earned the nickname battleship island. Mitsubishi worked the seam from 1890, and to house the workforce on that footprint the island went vertical: Japan's first large reinforced concrete apartment building went up here in 1916, and by the 1950s more than five thousand people lived on about six and a half hectares, at one of the highest population densities ever recorded anywhere, with schools, a hospital, shops and a cinema stacked among the shafts. The mine closed in 1974 and everyone left within weeks. Typhoons have been taking the buildings apart since. It was inscribed by UNESCO in 2015 within a Meiji industrial heritage listing, and landing tours run from Nagasaki.

What you actually see

• A walled island - reclaimed ground behind a sea wall, giving the battleship profile.
• Concrete apartments from 1916 - among the first large reinforced concrete housing in Japan.
• Extreme density - over five thousand people on about six and a half hectares in the 1950s.
• Collapse in progress - buildings coming apart under typhoons since 1974.

When to go

March to November, in calm weather. Half a day including the crossing.

Honest expectations

Landings are cancelled in swell and a substantial share of cruises never get ashore - check the operator's refund policy. Visitors are confined to a short walkway on the southern tip; the buildings cannot be approached. The crossing is rough. Booking ahead is required.

Nearby

Nagasaki harbour is the departure point; Glover Garden is above it.