The mystery of what is generally considered to be the greatest of the missing treasures of Europe may be about to be solved.

David Shukman on the trail of the Amber Room

Two rival teams in Germany and Lithuania believe they have located the Russian Czar's Amber Room, which was looted by the Nazis during World War II.

The Amber Room - often described as the "Eighth Wonder of the World" - is currently valued at about $250m.

It consisted of 100,000 pieces of carved amber panelling covering 55 square metres.

Amber plates depicting flowers and Prussian emblems

It was commissioned by Frederick I of Prussia in 1701, and later was presented to the Russian Czar Peter the Great.

It decorated the Catherine Palace, near St Petersburg, until September 1941 when invading German troops carried it off to Königsberg in East Prussia (now the Russian city of Kaliningrad).

But, when towards the end of the war, the Soviet Army recaptured the city, all traces of the Amber Room had vanished. And the mystery begun.

Hidden in a silver mine

Helmut Gaensel: believes the answer is in this silver mine

For five decades the KGB, the Stasi and many others have failed in the search.

But now, the German investigator Helmut Gaensel says he has found the spot where the treasure is hidden.

Former SS officers, living now in Brazil told him it was buried in a silver mine, 100 km south of Berlin and locals talk of great activity around the mine in April 1945.

Gaensel hopes that a tunnel he will open later this year will lead him to the Amber Room.

Buried in a lagoon

However, other investigators believe the Nazis did not remove the treasure from Konigsburg, but hid it on the shores of the Baltic Sea.

Mayor of Natinga: the lagoon might hide a valuable secret

Stasys Mikelis, the Mayor of the Lithuanian town of Neringa, believes that the Amber Room is buried under the murky waters of a lagoon close to his town.

He says the SS were seen towards the end of the war trying to hide wooden crates on the shoreline. The rise in the water level eventually covered the hiding place.