I'm in a small, damp room and there are three different-colored radiation suits hanging on the barren walls. Through the opening in a weighty steel door, I can see luminous green markings dotted along the dimly-lighted corridor. It may seem as if I'm in an updated version of "Star Trek" or having to plan my escape in some wacky quiz game. However, the space that confines me couldn't be more deadly serious: Civilians were supposed to come to this place for protection if mankind's insatiable appetite for destruction resulted in nuclear conflict.
In fact, a group of about 20 of us are in the Blochplatz atomic bunker, adjacent to Gesundbrunnen U-Bahn (subway) station, on a two-hour tour of Berlin. It's one of a series of unique outings run by Berliner-unterwelten that take you beneath the German capital to discover a fascinating world of former war fortifications.
The US, British, French, and Russian soldiers who won World War II (1939-1945) could never have guessed that such installations might be needed in Germany. Little did they know that just two years after that monumental struggle had finished, the Soviet Union would be their countries' new bitter enemy. The Cold War (1947-1991) had begun , stoking political and military tensions between the Eastern Bloc communist nations and the West.
"Nowhere was this enmity more apparent than in Berlin. In the first four years after the Second World War, as with Germany as a whole, it was split into East and West," our guide, Dominic, tells us. "In both cases, the former part was within the sphere of influence of the Soviet Union while what was left fell under British, French and United States jurisdiction," he continues.
The extreme paranoia of this time is evident when we enter another chamber in the bunker complex. Hanging on the walls are several stark original communist-era posters, their images a frightening collage of doom: dark gray radioactive-laden mushroom clouds; bug-like circular eye holes and elongated mouth parts that fill-out gas masks; and the metal-cased sentinels of death themselves, the actual nukes. Yet, the roughly translated words below one pictorial most characterize the apocalyptic mood of the age: "Book your trip to Europe, as long as there's still a Europe left."
Later, the charcoal-colored alloy mass of the ventilation system clings to the wall, as if some prehistoric robotic animal. Another visitor in our party and I simulate what needed to happen if it broke down due to a power shortage. We roll up our sleeves and hand crank it, but after just two minutes my arm feels as tired as if I've served 50 tennis balls. In fact, our effort isn't so bad: People were expected to do this for only about the same time, then others would take their place.
Actually, this "basic protection" bunker — in the sense of the level of defense it offers against a hydrogen bomb — could only hold so many people (1,318). And it had no food stores, as a stay here was intended to be only for up to 48 hours.
At Pankstrasse U-Bahn station, we visit a sturdier bunker, constructed in 1977. As well as being a subway stop, this "multipurpose" facility could shelter 3,339 men and women for up to two weeks.
We enter by means of an airlock, a necessity to avert radiation contamination. Reaching the sleeping quarters, rows and rows of metal-framed bunk beds, each one 70 inches long by 31 inches wide, stretch before us, under strip lights that had to remain on for 24 hours. And if that didn't induce sleep deprivation, refugees from the attack would also have had to deal with plastic mattresses, paper blankets, and humidity akin to that in a sauna.
After spending just 20 minutes in this bolt-hole, already the palpable sense of claustrophobia and sterility is getting to me. It's as if, by staring at the pale walls, corridors, and ceilings, they've already started to entomb my soul.
It would have been a lot worse for those who had to seek refuge, as they would also have had to contend with the cramped conditions — e.g., there were only 60 toilets, which worked out to a two to three-hour wait — and the boredom of not having anything to do. Not only that, there'd be the foreboding of what to expect on the bombed surface.
Thus, it's no surprise that in the kitchens, which would have been stocked with tinned produce like babies' milk, baked beans, and ravioli, we learn from Dominic that "There'd be no knives or forks, to stop anybody from harming themselves." Suicide prevention methods were also visible in the simple bathroom: unbreakable metal mirrors ensuring there wasn't any access to sharp edges; a lack of shower doors so no private space to be reckless; and all air pipes were public to thwart hangings.
What would have been quite desperate circumstances underground were detectable on the surface from 1961 when the German Democratic Republic (East Germany) built the Berlin Wall. The GDR "claimed this 96-mile-long concrete monstrosity was an 'Anti-Fascist Protection Rampart,' but its real purpose was to prohibit [its population from emigrating to West Germany," says my new guide, Cnaan.
I'm on my second tour, this time to explore a few of the ways East Germans tried to bypass the 12-foot-high barricade to get into West Germany. The almost instant erection on Aug. 13 of the wall and its guard towers cut through the hearts of families (over 50,000 were split), sweethearts, and friends inasmuch as many people were stranded on the wrong side and not permitted to return to their loved ones. In the preceding postwar period 1949-61, as many as 2.5 million East Germans had left for the West.
Much of this excursion occurs in an austere, 1980s-recommissioned civil defense shelter. On view are various maps, a photo exhibition, and a reconstruction of an escape tunnel. They help to illustrate the main three ways in which people endeavored to get past the Wall: via the sewer network, using the East Berlin subway system, or by digging their own passage.
Later, we arrive in an atmospheric mid-19th-century brewery at Bernauer Strasse, where there were seven escape tunnels (out of around 70 in Berlin, in total) within a distance of just 380 yards of each other.
"Although there was soft, sandy soil beneath the city, when people first started creating tunnels  it was often an arduous process with only fifteen inches of progress made on a bad day. Also, the East German police [the Stasi] were doing their utmost to catch you, or you could even be turned in by your comrades as was the case with [some]," Cnaan says.
In the end, including a plethora of ingenious methods (secret compartments in cars, a hollowed-out canoe, a shopping trolley, aerial wires, etc.) hundreds are said to have circumvented the Wall. Yet, unfortunately, at least 136 people — the exact figure may never be known — perished in the attempt. Twenty-five years ago, on Nov. 9, 1989, the monolithic boundary began to crumble, when East Germany allowed individuals to pass through its checkpoints. East German citizens and indeed the entire planet could breathe just a little bit easier, in the hope of a better future.
Xav Judd can be reached at firstname.lastname@example.org.