RALSKO, Czech Republic -- Judging by the smell of mold, the crumbling concrete, and the soot-covered electronics, it is hard to believe that just a few decades ago this abandoned bunker about an hour northeast of Prague was on the front line of a global military standoff. This base was once a heavily guarded, top-secret facility, as the nuclear-armed forces of the Soviet bloc and NATO squared off across Europe. In 1966, the Warsaw Pact conducted the Vltava military exercises in the southern part of what was then Czechoslovakia. According to the simulation, by the time the dust had settled the two sides had exchanged 252 nuclear strikes with a total explosive force of 59 megatons. The projected casualties: 57,000 soldiers and 2.5 million civilians dead. Forty-eight civilians for every killed soldier. The history of Soviet military activity in Czechoslovakia during the Cold War is still largely a dark secret, with many of the key documents held in closed Russian archives. Although it is clear that storage bunkers for Soviet nuclear warheads were constructed in the country and missile-launch systems were based there, it is uncertain whether the warheads themselves ever entered the country. "Czechoslovakia never had the opportunity to confirm whether there were warheads [in the storage bunkers]," Czech historian Prokop Tomek told Current Time TV. "One could only confirm this by studying the Soviet archives, which are now the archives of the Russian Federation."

For its size, Czechoslovakia boasted one of the most formidable militaries of the Eastern Bloc, with an army of nearly 200,000 men. "These days, politicians argue about how much to spend on the military," Czech journalist and former Czechoslovak soldier Jan Gazdik said. "We are supposed to spend 2 percent [of GDP, according to a NATO defense-spending agreement], but the Czech Republic does not reach this threshold and God only knows when it ever will. But back then, they spent up to 17.5 percent of GDP on the military. Even at the time, military people understood that this was destroying the economy." In 1961 and 1962, Czechoslovakia agreed to host nuclear-capable, truck-mounted missile systems provided by the Soviet Union, and three rocket brigades -- officially called artillery brigades -- were formed. Under the agreement, warheads for the SS-1 Scud-A missiles and Luna tactical rockets were stored in the Soviet Union and were to be brought into Czechoslovakia in an emergency within 18-22 hours. Throughout the decade, these units were modernized and upgraded with missiles with ranges of up to 300 kilometers capable of carrying warheads from 10 to 500 kilotons.

In 1964, however, the Warsaw Pact conducted an exercise in Poland that convinced Soviet military planners that the proposal to provide the warheads within 22 hours was hopelessly optimistic and that the risk they would be destroyed during transport was too great. Moscow decided to construct warhead storage facilities in East Germany, Poland, Hungary, Bulgaria, and Czechoslovakia. The following year, then-Czechoslovak President Antonin Novotny signed an agreement to build three warhead-storage bunkers by the beginning of 1967 according to plans and equipment supplied by Moscow. The facilities would be operated by Soviet troops, which was a significant development because prior to this agreement, Czechoslovakia was the only Warsaw Pact country that did not host any Soviet forces. Between 1966 and 1969, under the code name Javor (Maple), the three facilities were built at Milovice, Ralsko, and Misov. In total, the three sites had the capacity to store 576 warheads. They were built to withstand a direct hit by a 3-megaton nuclear bomb.

Officially, the facilities were explained as special communications nodes, which is reportedly what construction workers and Czechoslovak military guards were told. Only a dozen Czechs -- the president, prime minister, Communist Party head, and top military commanders -- knew the truth. The Warsaw Pact's military planning remains largely secret, but the 1989 Czechoslovak military doctrine has been released, historian Tomek said. "In the event of a military conflict, the first action would be for 15 Czechoslovak divisions to move in the direction of West Germany," he told Current Time, the Russian-language network run by RFE/RL in cooperation with VOA. "They would have taken enormous losses.... Western military attaches who studied our military and the Soviet military believed that the Soviet Army, which would have moved in behind the Czechoslovaks, were well-trained and obedient and their soldiers were accustomed to fighting to the end and winning.

"Their assessment of the Czechoslovak Army was much lower. They believed that discipline there was weaker, as was the desire to fight. The soldiers understood that their country was occupied." During the liberal Prague Spring period in 1968, some Czechoslovak military specialists came out against the Warsaw Pact's planning and proposed that Czechoslovakia develop its own military strategy based on its national interests. They issued the Memorandum-1968, which was signed by 42 officers and specialists, including the rector of the Prague Military-Political Academy. "That document alone angered the Soviet marshals to the point of interference," said journalist Gazdik. "As soon as Soviet forces entered the country [in August 1968], General [Vaclav] Prchlik, the rector and the leader of the group, was thrown in prison.... All the other Memorandum-1968 authors and signatories were kicked out of the military. They couldn't find work anywhere. So our best military theoreticians ended up eking out a living as translators, masons, or farmhands."

In the 1980s, the Soviets deployed SS-20 multiple-warhead missiles with a striking distance of 5,000 kilometers. This put all of Europe within range of missiles based in the Soviet Union. The United States responded by deploying Pershing-2 and Tomahawk missiles. A Czech children's book of the period included the poem: Mommy, Daddy, I'm afraid of the Pershing. Don't be afraid, dear child. The SS-20 is protecting you. The Soviet military, however, maintained the missile brigades in Czechoslovakia nearly until that country's Velvet Revolution in 1989. They were withdrawn in 1988 after the United States and the Soviet Union signed the Intermediate-Range Nuclear Forces (INF) Treaty. The abandoned storage facilities fell into disrepair and were targeted by looters and vandals -- all but one. The bunkers at Misov were used for various purposes after the Velvet Revolution, including as storage for communist-era currency that was removed from circulation. Now, history buffs have opened a private museum there. But the mystery of whether actual nuclear warheads were deployed in Czechoslovakia remains locked away in Russian archives.

"As a journalist, I have spent a lot of time looking [for this information], but I have not been able to clarify, and no one has been able to tell me, whether they came here or not," said Gazdik. "But I believe that nuclear weapons were here." Historian Tomek said he agrees that it is likely warheads were brought to the country in the late 1970s or early '80s when the confrontation with the West was at its peak. "Personally, I think that toward the end of the 1980s, during Gorbachev's perestroika and the beginning of disarmament negotiations, they had already been removed," he said. "If they were here, it was in the 1970s and early 1980s. But that is just a theory, based on the Soviet policies of the period."