Blå Jungfrun

Blå Jungfrun, also known as "Blåkulla", in English sometimes rendered literally as The Blue Maiden is a Swedish island in the Baltic Sea. It is situated in the Kalmar Strait, between the mainland province of Småland and the island province of Öland. Administratively, the uninhabited island is part of the municipality of Oskarshamn and covers an area of approximately 0.7 km² (0.27 sq mi) with a mean height above sea level of 86 m (282 ft). Home to black guillemots and a Swedish National Park since 1926, freedom to roam at Blå Jungfrun is limited with visitors prohibited from staying overnight on the island or making fires.

The island consists partly of bare rock with the remainder covered in dense hardwood forest. There are several caves and an ancient stone labyrinth from which it is forbidden to remove stones.

Geologically the island is an ancient inselberg rising from the Sub-Cambrian peneplain. After its formation in the Precambrian, Blå Jungfrun was buried in sandstone, which protected it from any further erosion, until it was finally freed from its sandstone cover in geologically recent times. In 2014 the island became object of archeological interest when a group of researchers discovered a cultural layer after probating the soil. At the time the authorities had given them the permission to only operate in a small area and could not take samples; three years later they were able to recover shards made out of quartz, which date to the Stone Age and had been probably produced by a settlement of hunter-gatherers. The exact age of the site remains uncertain, but it is estimated to have existed around 8500BC, about 10,000 years ago.