The Mystery of The Lost Amber Room

Six tonnes of amber displayed on gold-leaf walls and embellished with mosaics and mirrors decorated a chamber of the Catherine Palace near St. Petersburg, Russia. (Amber is fossilized tree resin)

These priceless amber panels, called an "Eighth Wonder of the World" were created in 1701 but disappeared during WW11.
Tsarskoye Selo, Catherine Palace. The Amber Room in 1917.
Originally designed for Charlottenburg Palace, the residence of  Frederick, the first King of Prussia, the complete panels were eventually installed at Berlin City Palace.

Peter the Great of Russia had admired the amber room during a visit to Berlin City Palace, and in 1716, King Frederick I's son Frederick William I presented the amber room to Peter as a gift.

With the German invasion of the Soviet Union in World War II, attempts were made to move the amber panels, but as they were fragile, they were simply hidden behind curtains.
Pushkin (Tsarskoe Selo). Catherine Palace (destroyed in World War II): interior, Amber Room. 1930s, PD
The Nazis found the room and on 14 October 1941, the amber panels arrived ta Königsberg in East Prussia, for storage and display in the town's castle.

In November 1941 the Amber Room was to be exhibited at Königsberg Castle.

Then, in August 1944, Königsberg was bombed by the Royal Air Force and then further damaged when occupied by the Red Army on 9 April 1945.

The Amber Room was never seen in public again,

Various people claimed they saw the amber room loaded onto a German ship, Wilhelm Gustloff, which left Gdynia on 30 January 1945, part of Operation Hannibal,. The ship was then torpedoed and sunk by a Soviet submarine.

Soviet general-secretary Leonid Brezhnev ordered the destruction of Königsberg Castle in 1968, making it impossible to search for evidence of the amber room here.

In October 2020, Polish divers found the wreck of the SS Karlsruhe, also part of Operation Hannibal, but the amber room was not found in the wreckage.