Back in August 2019 American archeologists excavating the site of a suspected ancient Roman villa near the modern city of Cologne came across a surprising artifact of more modern vintage; a Cold War era Soviet radio buried near a nuclear research center and a former American military base. The R-394KM radio was in a hermetically sealed metal container. When opened you could hear the air escaping the seals, which were still intact. The radio was factory-fresh and wrapped in paper containing radio frequencies, apparently for the Russian agents who would use it. The batteries had lost their charge but with fresh batteries, the radio still worked. The radio was apparently intended for use by German speaking agents because the radio controls were labeled in English while the manufacturers’ data plate was in Cyrillic (Russian) alphabet. This indicated the radio type and date of manufacture; 1987. The radio appears to have been buried in 1988 or 1989 before the communist government of East Germany fell in 1989 and the Soviet Union collapsed in 1991.
The radio found outside Cologne was apparently intended for Russian or East German agents who operated in large numbers in West Germany during the Cold War. After the Cold War ended and Germany was reunited there was a search for such buried weapons and equipment. Buried equipment for spies, or special operations troops, was common in West Europe during the Cold War. American Special Forces in Berlin, which was surrounded by Russian occupied East Germany during the Cold War, buried weapons caches all over American occupied West Berlin. This was a precaution in the event of a Russian attack and for the use of American personnel and West German agents who would be working with them.
The same practice was employed throughout West Germany by the American CIA, which planned to maintain a network of spies in parts of West Germany that would be overrun in a Soviet invasion that never came. The buried weapons often included other equipment, like radios. After the Cold War ended all these caches were retrieved. That same could not be said for caches buried by Russian and East German spies. Some information was obtained about these caches after the Cold War ended and they were removed. In doing that it was discovered that location data on many other buried items had been lost as the communist governments collapsed.
East German intelligence, which worked closely with their Russian counterpart, the KGB, deliberately destroyed many of their records pertaining to espionage operations before the East German government was completely out of business in 1990. This was done to protect German Stasi (secret police) crimes as well as the identity of Russian agents still active in what had been West Germany. So it was known that caches were still out there and police are warned to remain alert in case someone finds one of these caches of weapons and decides to sell the weapons rather than report them.
For a while, it was feared that the Soviets had also buried some small nuclear weapons as well. These buried “backpack” nukes turned out to be a myth, even though they did exist and the U.S. planned to use them if there was a Russian invasion, for demolishing infrastructure that would delay the advancing Soviet forces. These mini-nukes were eliminated after the Cold War, along with spy radios buried elsewhere in Western Europe for use by secret local agents recruited to provide information in case of a successful Soviet invasion.
The radio found outside Cologne was typical of what was used by Soviet era spies. It could transmit messages to receivers over 1,200 kilometers away. The Soviet agents would not have to use the radio to receive information. For that, they could rely on a “numbers station.” This is a special radio station that uses a specific shortwave radio frequency that periodically (on pre-arranged dates and times) broadcasts sequences of numbers. These broadcasts often last a few minutes then that channel goes silent. Numbers stations were a popular 20th century technique for sending secret messages to agents in foreign nations or combat zones. It began during World War I, with Morse code used instead of a spoken voice. Using short wave a numbers station deep inside Russia could broadcast the numbers worldwide.
After the Cold War ended there were still a few nations using numbers stations, most notably Cuba, China, Taiwan, Israel and, until 2000, North Korea. In 2016 North Korea activated, for the first time since 2000, one of its numbers stations. Given the frequency used and the strength of the signal, the audience for these new North Korean messages was in South Korea, China or Japan. Analysis of the audio indicated that the North Koreans were using Cold War era Russian (Soviet) broadcast equipment. Apparently this gear was put in storage in 2000 and revived for the new broadcasts.
For nations with international Internet access, and this does not include North Korea, there are more effective Internet based methods for sending secret messages. North Korea is known to have used these Internet based methods so it is a mystery as to why they have revived their numbers station broadcasts. Then again it could just be another ploy to frighten their enemies, which is just about everyone, especially South Korea, the United States and Japan. These three nations do not appear alarmed by the broadcasts, but that could be said for most North Korean threats.
Germans still have to be alert about buried explosives because about a hundred unexploded bombs and shells are found each year, mainly by construction crews in urban areas. The most dangerous of these are bombs dropped during World War II that did not explode. Some of these bombs weigh a ton or more and nearly all are safely disarmed by the bomb disposal terms, who then carefully remove the bomb for disposal. That means explosives removed and neutralized while the casing becomes metal scrap. Sometimes the bomb disposal team determines that the fuze is too unstable to be safely disarmed and the area is evacuated and the bomb destroyed by detonating using another explosive. That is rare but there are times when there is no other choice but to evacuate a wide area and then repair lots of blown-out windows and other damage.
It’s not just aircraft bombs. Most of the explosive items unearthed are smaller ones like grenades, mortar shells, rockets and mines. Many bombs, artillery and mortar shells (over ten percent, for some manufacturers) did not explode when they were supposed to but just buried themselves into the ground. These shells are still full of explosives, and often have a fuze that, while defective, is often still capable of going off if disturbed. Other munitions were left in bunkers, or elsewhere on the battlefield, and got buried and lost. Most of these lost munitions eventually get found by farmers, or anyone digging up the ground for construction. Heavily bombed cities during World War II still suffer from construction crews unearthing unexploded bombs. In Russian cities, you tend to find lots of artillery shells that were fired by both Russian and German troops.
The problem goes back farther than World War II. Unexploded munitions from the American Civil War, which ended in 1865, are still showing up, and some of them are still deadly. But these 19th century items are rare. Currently, over a thousand World War II munitions are discovered each year in Europe.
The buried radios and other modern spy gear are a 20th century, mostly Cold War (1949-91) era problem that is not nearly as widespread as the unexploded munitions.