Just over half a century ago, during the pre-dawn hours of an August Sunday, construction began on the Berliner Mauer (Berlin Wall). Bernauer Strasse residents woke up to find the center lane of their East Berlin street barricaded by the beginnings of a 12-ft.-high "anti-Fascist protective barrier"—which suddenly separated them from the adjacent Wedding neighborhood. There it stood: Europe's ultimate symbol of Cold War tensions and ideological divisions.Berlin Wall Art

Well-planned despite the hasty buildup, it cost 16,500,000 East German Mark ($3,638,000) and had formidable and forbidding dimensions. Curving and zigzagging around and through the widespread area, overall circumference amounted to 96 miles/155 km. First came crude cinder blocks and coils of barbed wire, eventually replaced by 45 sections of pre-cast concrete slabs. Twenty-seven miles/43 km. of them were sufficient to effectively separate East from West Berlin. Average width: 14.7 inches. The thickness, plus steel reinforcing rods and parallel deep-dug trenches, made it impossible for even a heavy-duty truck—racing at full speed—to slam through to the opposite "free" side. Smooth metal tubing atop the slabs repulsed grasping clamps and desperate rope-climbers.

Impervious to urban realities, planners allowed the hateful Wall to cut through 192 streets, enough to hugely disrupt the livelihoods of 60,000 daily East-to-West commuters while causing traffic jams, delays and detours. Overall, the setup included powerful floodlights, 302 watch towers and teams of stern, green-uniformed Grenztruppen border guards. Round-the-clock engineering and construction required 40,000 workers.

Mass East-to-West Exodus

What prompted such huge expense and furious effort? Primary answer: an increasingly acute "brain drain." By 1961, an estimated 2,600,000 East German citizens, anxious for governmental democracy and better living conditions, had decided to move west, usually by merely departing through inner-city Berlin's seven border checkpoints. In addition, police and militia reported 5,000 attempted, mostly successfully brazen escapes during the repressive, economically tight-fisted GDR era.

Responding to the crisis on August 12th, GDR premier Hans Modrow ordered the closing of all borders. Hence the Wall's earliest appearance during the evening hours, destined to remain in place for the next 28 years. For visitors entering West-to-East, GDR officials mandated 1:1 currency exchange from Deutsche Mark (minimum DM 25) to less-favorable ostmarks—no refunds, no matter what the amount.

You'll learn a lot by visiting two permanent exhibitions. The American and Soviet military zones bumped into each other (seldom pleasantly) at Checkpoint Charlie, where Kreuzberg's Friedrichstrasse and Zimmerstrasse intersect. Here the Mauermuseum recalls East-to-West escape strategies: tunnels, kites, hot-air balloons, boats and makeshift gliders—also by stuffing fed-up Ossies in little trunks of clunky little Trabi sedans. Admittance: adults €12.50, students €9.50. Friedrichstrasse 43-45, tel. (030) 2537 250; www.mauermuseum.de.

Additional coverage can be found at the no-charge Berlin Wall Documentation Center, where the Mitte's working-class Bernauer Strasse meets Gartenstrasse. Along with dioramas, digital archives and audio stations, an observation tower provides overviews of what had been a tightly secured system. Bernauer Strasse 111, tel: (030) 467 9866-66. Get there by transiting to the Nordbahnhof S-Bahn station.

Right after reunification made worldwide headlines, lengthy stretches of the concrete slabs were dismantled. Others fell victim to "wall-peckers," hammering, gouging, chipping and chiseling with a capitalist eye toward souvenir-trade riches. Surprisingly, however, some sizable sections can still be seen-touched-pondered-photographed. Otherwise, pavement bricks and four kilometers of red-painted Rote Faden stripes merely hint at where the Wall was but is no more.

Friedrichshain & Prenzlauer-Berg

A well-known exception is Friedrichshain's half-mile-long East Side Gallery facing Spree-canalside Mühlenstrasse, southeast of Alexanderplatz. Since 1990, this part of the intact Wall has been slathered with 106 anti-establishment paintings, cartoons, scribbled graffiti and rebellious slogans. Elsewhere, at Niederkirchnerstrasse in Kreuzberg, the Wall penetrates basement chambers now known as the Topography of Terror, referring to its Third Reich existence as the prison-and-torture netherworld run by Gestapo-SS chiefs Heinrich Himmler and Reinhard Heydrich. Free admittance.

At the eastern edge of Tiergarten greenery, a short restored segment on Ebertstrasse connects two major landmarks of imperial Germany: the Brandenburg Gate and the Reichstag. Toward the park's opposite side, sightseers aim for half a dozen propped-up weather-beaten slabs on the Stresemannstrasse side of the flashy Potsdamer Platz mega-complex.

A 656-ft. Wall remainder slithers beneath the Bornholmerstrasse S-Bahn transit bridge, on the western edge of ex-GDR Prenzlauer Berg. The span became instantly historic when borders were opened at 9:20 p.m. on November 9th, 1989. That prompted a surge of vehicles and 20,000 jubilant pedestrians, crossing in both directions from the two Berlins. Also in Prenzlauer Berg, walls and death strips between Schwedter Strasse and Schönhauser Allee were replaced—in 1994—by the Mauerpark, where 20,000-seat Friedrich-Ludwig-Jahn Stadium hosts Bundesliga Fussball matches and Max-Schmeling-Halle is a sports-and-showbiz venue. Here, too, an outdoor flea market draws Sunday bargain-hunters.

For high-tech orienteering, think about borrowing a hand-held GPS gadget called the Walk the Wall Mauer Guide—combining 22 touch-screen maps with audio directions. (English version available). Cost is €8 (four hours), €10 (full-day). Rent at Checkpoint Charlie, Brandenburg Gate and on Bernauer Strasse. Perhaps a better alternative for Smartphone users is the $2.99 app Berlin Wall Walk downloadable at the iTunes store or by visiting gpsmycity.com/.

West Berlin Encircled

West Germany's capital city was surrounded by an expanded ring of checkpoints and watch towers, amounting to 99 miles/160 km of "outer borders." In 2006, that encirclement became the Berlin Wall Trail. Comprising 14 signposted sections and 40 info stations, the hiking-biking route loops through outlying Wannsee, Zehlendorf, Steglitz, Helmsdorf, Schönefelde and other suburban locales.

Contact Berlin Tourism.