Hashima Island, Nagasaki Prefecture, Japan

In 1959, the 15-acre island's population reached its peak of 5,259, with a population density of 835 people per hectare (83,500 people/km2, 216,264 people per square mile) for the whole island, or 1,391 per hectare (139,100 people/km2) for the residential district.
As petroleum replaced coal in Japan in the 1960s, coal mines began shutting down all over the country, and Hashima's mines were no exception. Mitsubishi officially announced the closing of the mine in 1974, and today it is empty and bare, which is why it is called Ghost Island. Travel to Hashima was re-opened on April 22, 2009 after 35 years of closure.