Karl Sperber, 78, from the town of Burgebrach near Bamberg, Bavaria, has been constructing 'Sperber City' since he was 13-years-old.
Inspired by cities, such as Frankfurt am Main, New York and Chicago, the retiree who used to work in the furniture industry has built his city from cardboard, turning shoe boxes into skyscrapers.
His life's work, which he's been doing for almost 65 years, is impressive. More than 4,000 houses have been built throughout the decades.
Covering more than 40 square meters, some of his collection can be seen in the exhibition space of a former furniture store in his town.
Sperber City. Photo: DPA
Sperber is aware that he has an extraordinary hobby. “Some of my friends say I'm crazy,” he says.
But when constructing and building his cardboard houses, he says he's always been able to simply switch off from life whatever his age.
Sperber spends up to three hours a day in his crafts room working on his hobby, which needs few tools: he can get to work with a ruler, pencil, glue and cardboard.
This is how his first constructions arose more than sixty years ago – “and they still hold,” he said.
“I build more than 100 houses a year,” says Sperber. Each house takes its own construction time. “It always depends on the style, on the architectural style.”
Modern buildings can be built relatively quickly, houses from earlier periods are more complex because of their intricate details.
Sperber City is inspired by large American cities, which are famous for their skyscrapers.
But the pensioner has not visited these places. “I don’t like flying,” he says. His metropolis, therefore, came from his imagination but he's also inspired by German cities, such as Frankfurt am Main.
To see his full collection would be difficult. He would need a lot more space, and has to settle on storing his creations away.
“I would need 100 square meters,” says Sperber.