Divers exploring a 'UFO-shaped' object in the Baltic sea say that the strange, curved object might be a Nazi device lost beneath the waves since the end of the Second World War.
Sonar scans have shown that the device, raised 10ft above the seabed and measuring 200ft by 25ft, could be the base of an anti-submarine weapon.
The weapon was built with wire mesh which could have baffled submarine radar, leading enemy craft to crash - much in the same way as turning out a lighthouse could be used as a weapon against shipping.
But now former Swedish naval officer and WWII expert Anders Autellus has revealed that the structure - measuring 200ft by 25ft - could be the base of a device designed to block British and Russian submarine movements in the area.
The huge steel-and-concrete structure could be one of the most important historical finds in years.
Autellus claims it would have been built of double-skinned concrete and reinforced with wire mesh to baffle radar - which could explain why the dive team's equipment repeatedly failed near the mystery object.
‘The area was vital to the German war machine because most of the ball bearings for its tanks and trucks came from here. Without them the German army would have ground to a halt,’ explained one expert.
‘This device dwarfs anything ever found before and is an important weapons discovery,’ they added.
Explorer Stefan Hogeborn - who is studying the images for the Ocean X diving team - agreed: ‘It is a good candidate for the answer to this mystery. The object lies directly underneath a shipping route.’
‘It would be of enormous weight in steel and concrete. Other Nazi anti-sub anchoring devices were nowhere near as large,’ he added.
While the Ocean Explorer team is understandably excited about their potentially earth-shattering find, others are slightly more sceptical and are questioning the accuracy of the sonar technology.