The Densest Place on Earth Is Now Empty

Hashima Island is 6.3 hectares of seawall and concrete, sticking out of the water 15 km from Nagasaki. From a distance it looks like the Japanese battleship Tosa, which is where the nickname Gunkanjima comes from. In 1959, more people lived on this rock than live in some American counties.

The coal seams ran out under the seabed, and the apartments ran up. Mitsubishi bought the island in 1890. By 1916, they had built Japan's first large reinforced concrete building — a seven-story miners' block that had to be reinforced because typhoons would otherwise pull a wooden tenement off the rim. More blocks followed. Schools, a hospital, a Shinto shrine, a movie theater, a pachinko parlor: all stacked on top of the mine head.

At the 1959 peak, 5,259 people were living at a density of 835 per hectare. Children walked to school through interior staircases that connected the buildings, because the wind off the water could knock them down. The rooftop of one apartment was the elementary school's playground.

Then the country switched fuels. Japan moved from coal to petroleum through the 1960s, and Mitsubishi closed the Hashima mine in January 1974. On 20 April that year, the last residents boarded a ferry. The island sat sealed for 35 years.

It reopened to visitors on 22 April 2009. More than 95 percent of the island is still off-limits — the buildings are crumbling — but you can stand on the southern walkway and look up at the school, the apartments, the wind, and the absence of 5,259 people.