Warsaw:
Nazi bombs left Warsaw as little more than a smouldering heap of rubble at the end of World War II.
Now, nearly seventy years later, the charm of the pre-war Polish capital dubbed the "Paris of the north" has been brought back to life for the first time thanks to a new film, using three-dimensional computer imaging.
Whether from the eye of an eagle soaring over the skyline, a pigeon flying down city streets, or passengers on a tram, "Warszawa 1935" invites viewers into the lush squares and parks of the city centre, a vanished world that very few still recall.
For Stefan Zoltowski, now 84, seeing "Warszawa 1935" rekindled memories he thought were long lost.
"It's impressive. I saw part of the street on which I spent my childhood," the retired physician who grew up on Zlota (gold) street in the heart of Warsaw told AFP.
The Nazis razed the apartment building belonging to his family to the ground during the 1944 Warsaw Uprising.
Over 80 percent of Warsaw was destroyed by the Nazis, and more than 700,000 of its 1.3 million pre-war residents perished under German occupation between 1939-45.
Today, a shopping mall and the landmark Stalinist-era Palace of Culture built by the Soviet Union in socialist-realist style just after the war stand on the streets where Zoltowski once played with childhood friends.
The 237 metres (299 yards) high Palace of Culture is now flanked by parking lots, parks and capitalist-era sky-scrapers, which have transformed the city centre almost beyond recognition over the last two decades.
The new 3D film which shows the city as it was before its destruction and subsequent communist and capitalist-era revamps, fills a deep yearning for "the Warsaw we miss" says Ryszard Maczewski, head of the Warszawa1939.pl foundation working to document the capital's pre-war design.
"No one has done this before. It's been quite a challenge," film producer, Ernest Rogalski, told AFP at the film premiere.
The production team scoured the Internet and the national archives in search of photos and city plans that could serve as the basis for its virtual reconstruction.
As luck would have it, the national archives held detailed late 19th century plans made by celebrated British civil engineer William Lindley for the city's waterworks, which proved to be a treasure trove of information. His waterworks are still in use today.
"It's a map-making masterpiece," says Pawel Weszpinski, a cartographer with Poland's National Archives.
Only three European cities of the era - Warsaw, Frankfurt and Hamburg - were mapped at a scale of 1:200 with such intricate precision. Even trees in Warsaw were drawn to scale.
Meanwhile, pre-war commercial registries gave clues about the location of shops and other businesses, allowing the movie makers to put up advertising logos and company signs in just the right spots.
But getting all this information on the silver screen took a whopping 12 terabytes of digital imaging in what can only be described as a programming project of mammoth proportions.
"It took enormous computing capacity to render our three-dimensional images. We used servers at the Polish Institute for Nuclear Research and at a data centre in China. In Europe, nobody wanted to help us, for fear of overloading their servers," film director Tomasz Gomol told AFP.
Their digital city-tour is quick, just 20 minutes, and does not allow the viewer to linger and admire its richness of detail.
"That inconvenience will change soon when the film comes out on DVD and Blu-ray," says Gomol as he reveals plans are afoot for a sequel digital journey into Warsaw's forgotten past.