A Nazi tunnel in Poland built using forced labour has been opened for the first time since the Second World War.
The tunnel is part of an underground mining and construction project code-named Komplex Riese by the Nazis.
According to Project Riese, an international group of historians exploring the area in question, "extensive construction work on a number of underground shelters and tunnels" took place in the Owl Mountains between 1943 and 1945.
Although the purpose of the facilities remains unclear the website says that, "German sources suggest that they were supposed to be turned into a huge underground shelter covering more than 35 square kilometres, with one of Adolf Hitler's Führer Headquarters at its centre".
According to Project Riese, the complex was also intended to be used as a refuge for the leading members of the military as well as a safe place for certain industrial facilities.
Waldemar Lyczak, a worker helping to open the tunnel, told a television crew that much of it was blocked by rubble.
"We've been successful because we had to dig through part of it that had collapsed which wasn't as big as we thought," he said. "We went several dozen more kilometres down the tunnel and unfortunately came across another collapse."
The construction work was done by forced labourers from concentration camps. Many of them died of disease, malnutrition, exhaustion, or mistreatment by guards.
"The Germans were keen to make progress and forced the prisoners to be obedient," said Lyczak. "Many suffered ill health or died here to make the tunnels."
The tunnel is the latest in the system to be opened. According to Project Riese, three others are run by private owners and can be visited by tourists.
APTN