Scene in Berlin

All cities are constantly evolving entities, and because of the radical ups and downs of its history, Berlin has had no choice but to change more than other urban centers. Still, there's something unusual about the pace and creativity with which Berlin spaces are radically redefined and put to other uses.

Urban recycling has become a habit, almost a compulsion.

Take what is still our main airport. Visitors who fly into Tegel may not know this, but they are landing in what is intended to become an academic campus. According to a "master plan" drawn up by a public-private consortium, the 460 hectares of Tegel Airport will be converted into a technology park, including a technical university, when and if the city's long-delayed new air hub Berlin-Brandenburg International ever opens its gates.

Walking through the futuristic, hexagonal main terminal, so totally state-of-the-art when it was built back in 1974, it's tough to imagine techie students talking diffusers and Internet apps here. In Berlin, even the best laid plans of mice and men can morph into something completely different.

In 2008, the city's other major airport Tempelhof closed, and since then the massive grounds have served as a playground for rollerbladers, kite-surfers and all who enjoy doing reckless-looking things with sails and/or on wheels.

While politicians and local advocacy groups squabble about the site's future, picnickers enjoy the unique atmosphere of the airport's 1930s brutalist aesthetic as a backdrop. It's as though New York City suddenly got a second Central Park, designed by Giles Gilbert Scott.

Berlin's city planners continue to debate. But residents have already recycled Tempelhof and made it into something one of a kind.

A great place to skip school

Urban re-contextualization is more likely to be successful, one might argue, when the initiative comes from the bottom up. And with its ruptured history, Berlin offers residents no shortage of playground upon which to exercise their imaginations.

One good example is the Gleisdreieck park on the border between the districts of Schöneberg and Kreuzberg. The site was once home to a crossing point for three major railway lines, but the Berlin Wall severed the connections, meaning that for almost three decades the tracks here literally went nowhere.

Local residents petitioned the city government to allow them to use the derelict site as a park, and in 2011 the eastern half of the facility opened. The western half will follow suit in 2013. For the landscaping, sand excavated from a major construction site on nearby Alexanderplatz was used.

Otherwise, the architects didn't try overwrite the site's history. Train tracks still lead into subsequently planted copses of trees; visitors sunbathe on the steps of preserved railroad buildings. The park was a finalist for a European Garden Heritage Network's European Garden Award in 2012.

More importantly, though, it's a big hit with local residents. On a sunny October morning, a mother watching her kids play on a jungle gym called the "Forest of Poles" says the new relaxation facility has improved the quality of life in the neighborhood.

The teenagers doing skateboard tricks in one of the hollow bowls of asphalt in another section of the park only grin and shrug when asked whether they're supposed be in school. Why waste such a great day inside when you can have fun horsing around a former freight hub?

Growing their own

Enterprising Berliners are also proving that you don't need any state help at all to reclaim and refocus a stretch of urban landscape. Further east in the less well-healed part of Kreuzberg, the epicentre of what was West Berlin's squatter and punk scene, people now meet up to grow vegetables.

In 2009, two young fellows named Robert Shaw and Marco Clausen rented an abandoned lot near a traffic circle, cleared a decade's worth of accumulated trash and founded a communal garden. There was no master plan. The idea was to let "Princesses Garden" just develop … er … organically.

And grow it has. The project has attracted the attention of both the New York Times and CNN, and Clausen has published a book about it. On the average day, you're likely to hear as much English as German spoken between the rows of lemon balm and sorrel, grown in re-utilized plastic bread crates and gunnysacks.

The fall is the time to harvest potatoes. There are groups of volunteers, mostly women, throughout the garden, and the idea is to wrap them in clay and then roast them.

"I zink it must be zin," says a Frenchman named Pierre, and the women set about flattening the clay with rolling pins, while a group of tourists hustles to photograph the potatoes.

No one knows whether the clay-roasting is going to work, and no one really seems to care. The point is the process, not the end result.

Much the same could be said about the entire city. Berlin has always been just as much an adventurous project as a place. And almost a quarter of a century after the Fall of the Berlin Wall, the two halves of the city have indeed grown together - without ever forming a finished whole.