Fire engulfed Hitler's mountaintop Eagle's Nest retreat in Bavaria last month

Perched on a ridge high up in the spectacular scenery of the German Alps lie the burned-out ruins of a mountain house called The Eagle's Nest, which is now at the heart of an intense debate about Germany's Nazi past.

Known in German as Kehlsteinhaus, the retreat was built by the Nazis in 1938, and frequented by Adolf Hitler and other high-ranking Nazis and their guests. After World War Two it was classified as a historical monument recalling the Nazi era.

Last month it was gutted by fire in a suspected arson attack, and some believe it should be completely destroyed, the site returned to nature and all memory of its Nazi past forgotten.

But others want it either partially or completely rebuilt, wary of the risk of turning it into a site for Neo-Nazi pilgrimage at a time when Germany is witnessing the resurgence of the far-right.

Germany has an "everlasting responsibility to communicate, to deal with our Nazi past", said Isabel Heinemann, professor of contemporary history at Munich's Ludwig-Maximilians-Universität (LMU).

But rebuilding the site completely, she warned, would mean putting "highly ideologised or highly ideological architecture" back in place.

Adolf Hitler used the mountain retreat to welcome guests

Before it was burned down during the evening of 23 October, the Eagle's Nest had been a popular tourist attraction, owned by the state of Bavaria and operating for many years as a restaurant.

Visitors would take a bus and then ride the original brass and mirror-panelled lift through the mountain to the Kehlsteinhaus to savour the magnificent views above the town of Berchtesgaden.

Once there, they could eat sausages in the beer garden on the Obersalzberg at 1,834m (6,017ft) above sea level, overlooking the Alps.

Unlike Hitler's nearby summer residence, the Berghof, which was bombed in World War Two and demolished in 1952, the Eagle's Nest survived the war.

Tens of thousands of tourists visited each season, providing an important source of income to the region.

In the 1990s, amid concerns that the site did not do enough to confront the crimes of the Nazi past, a museum, the Obersalzberg Documentation Centre, was opened close by.

Before it was burned down, the Kehlsteinhaus or Eagle's Nest had long been a tourist destination in Bavaria

Around 15 years ago, a photo exhibit was opened in the Kehlsteinhaus about its history.

Although the Eagle's Nest itself was "largely destroyed" by the fire, according to police, the documentation centre survived unscathed.

The authorities have not commented on a possible motive, but a 33-year-old man with a history of mental illness has been detained in a secure psychiatric hospital on suspicion of arson.

Man arrested after fire at Hitler's mountaintop Eagle's Nest retreat

Some feel this is the moment to allow the site to fade into history.

"It's been torched now. It's been destroyed. I think they should just clear away the rubble and leave the mountain as it should be in its natural state," said Prof Sir Richard J. Evans, a specialist in Nazi Germany at the University of Cambridge.

That has happened with "quite a few other Nazi sites", he argued, including the bunker in Berlin where Hitler killed himself: "The bunker was filled in with concrete and a children's playground put on the top of it on the ground."

The Kehlsteinhaus was just "a Nazi vanity project" since romanticised by the name Eagle's Nest, he said.

Police say the old Nazi retreat was largely destroyed by last month's fire

But Bavaria's authorities take a different view about the site's future.

Both the state's interior minister, Joachim Herrmann, and its minister for the arts, Markus Blume, have spoken out in favour of rebuilding the Kehlsteinhaus.

"We can hardly leave a ruin standing there," Herrmann said.

Sven Keller, head of the Obersalzberg Documentation Centre, believes it is important not to leave the site in ruins, as that could encourage Neo-Nazi pilgrims, who would be able to hike up there completely undisturbed.

"We have quite some experience at Obersalzberg with what happens if we clear those sites. Hitler's Berghof was demolished in the 1950s, and in our experience, this does not remove such sites from the mental maps of people," he told the BBC's Today programme.

Nor does he believe "a one-on-one reconstruction" of the site is possible, and Blume has made clear on Bavarian radio that "it should not and must not cost the taxpayer anything".

After Hitler's downfall, US soldiers captured the mountain-top retreat and are seen relaxing here on 4 May 1945

Herrmann said they would look for a sensible solution in consultation with historians, given the historically complex circumstances surrounding the building.

Heinemann, who also heads the Leibniz Institute for Contemporary History, believes full-scale reconstruction should be "out of the question".

"I rather think we can document the state left by the fire and also document the historical remains of the Kehlsteinhaus, and then reconstruct parts in a modern design, to make clear the different layers of time that can be seen in this building," she told the BBC.

Germany and Austria have long struggled to deal with the fraught legacy of buildings and sites connected to the Nazi era.

With the recent rise of the far-right AfD and the Austrian Freedom Party, the debate over Erinnerungskultur (Culture of Remembrance) has taken on a new urgency.

A row broke out recently in Germany when AfD and conservative CDU councillors in a town in Saxony decided to ban "stumbling stones" memorials - embedded small brass plaques in the streets - to victims of the Nazis.

In Austria over the summer, a police station was opened in the house where Hitler was born in Braunau am Inn. It followed years of controversy about how the house should be used.

The Austrian government said the police presence would help prevent neo-Nazi pilgrims.

But others had wanted the house to become a centre of responsibility, actively confronting the Nazi past.

As one resident of Braunau am Inn told me, it was a delicate balance between how much to remember and how much to forget.

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