This is 99% invisible. I'm Roman Mars.

During the Cold War, a so-called Iron Curtain separated eastern and western Europe,

communism from capitalism, the Soviet Union, from everyone else.

In some places it was an actual wall, like in Berlin,

and in other places it was just a barbed wire fence.

This border was long, stretching from northern Finland through Central Europe.

It covered 12.5,000 kilometers or almost 8,000 miles.

And all along this 8,000 mile border, there was a no-man's land, a couple hundred yards across,

where there was almost no human activity.

When the Cold War ended and the walls and fences came down, people noticed something interesting.

That's reporter, Emmett Fitzgerald.

This neglected strip of land had become a productive ecosystem.

With forests and fields, it was a haven, particularly for migratory birds.

Soon after the Berlin Wall fell, conservationists from east and west came together to protect this accidental refuge for birds and animals.

Because the no man's land was so long, they realized that it could link habitats throughout

Central Europe. Today, the so-called European Greenbelt traces the path of the old iron curtain.

It connects national parks and nature preserves and helps animals move around in a landscape dominated by humans.

It's what's known as a wildlife corridor.

Wildlife corridors can link two extremely large habitats,

like two national parks or two national forests

in the national park, say across a very large freeway.

Or it can link relatively small fragments of habitats within very developed metropolitan areas. That's Louise Mazzingo. of

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