10 Nail-Biting Espionage Operations of the Cold War

Espionage existed long before the Cold War, but the decades-long standoff between the United States and the Soviet Union transformed it into a contest of cryptanalysis, surveillance, deception, and increasingly sophisticated technology. The operations from this period have inspired countless books and movies… or at least the operations we know about.

Many remained classified for decades, and some may never be fully understood. Others succeeded even though enemy agents knew about them from the beginning. In almost every case, the real story proved more intriguing than the fiction it inspired.

Related: Ten Ancient Tales of Spies and Espionage

10 The Venona Project

The Venona Project was a U.S. Army Signal Intelligence Service operation launched during World War II and later continued by the National Security Agency. Its original purpose was to examine encrypted Soviet diplomatic communications, but the messages soon revealed extensive Soviet espionage activity. The program officially ran from February 1943 until 1980.

American cryptologists required nearly two years to make their first major breakthrough. Soviet intelligence services had accidentally reused pages from supposedly unbreakable one-time pads, giving analysts the opening they needed. Even then, the work was painstaking. Names were often replaced with cover names, messages were incomplete, and analysts sometimes spent years identifying a single person.

Venona eventually provided evidence about Soviet intelligence networks operating inside the United States and other Western countries. Its decrypts helped corroborate investigations involving Julius and Ethel Rosenberg and revealed Soviet attempts to obtain information about the Manhattan Project. Approximately 3,000 translated messages were ultimately released to the public beginning in 1995.^[1]

9 Operation Gold

Operation Gold, better known as the Berlin Spy Tunnel, was one of the most ambitious early espionage operations undertaken by the CIA and the British Secret Intelligence Service. Beginning in 1953, the two agencies planned to dig beneath divided Berlin and tap underground cables carrying Soviet military communications.

The completed tunnel stretched almost 1,500 feet (457 meters) from Berlin’s American sector into the Soviet-controlled eastern sector. From May 1955 until April 1956, Western intelligence teams used it to record around 50,000 reels containing approximately 450,000 telephone conversations. Translators continued processing the enormous collection for years.

Unknown to the CIA, the Soviets had known about the operation since its planning stages. British intelligence officer George Blake was secretly working for the KGB and had warned Moscow about the tunnel. Rather than expose Blake, the Soviets allowed the operation to continue before arranging its apparent accidental discovery in April 1956. Their propaganda effort backfired, as much of the international press responded by admiring the tunnel’s audacity and technical ingenuity.^[2]

8 The Farewell Operation

In 1981, French intelligence received an extraordinary offer from Vladimir Vetrov, a KGB officer assigned to evaluate intelligence stolen from Western scientific and technological programs. Disillusioned with the Soviet system, Vetrov agreed to provide France with classified material under the code name “Farewell.”

Over the following months, Vetrov photographed and supplied around 4,000 KGB documents. Together, they exposed a vast Soviet program dedicated to acquiring Western technology through spies, recruited sources, and front organizations. The material identified hundreds of intelligence officers and agents involved in the effort and revealed which technologies the Soviet Union was most determined to obtain.

French president François Mitterrand informed U.S. president Ronald Reagan about the source, and the intelligence was shared with the CIA. Western governments responded by expelling or neutralizing Soviet operatives and tightening controls around sensitive technology. Vetrov was eventually arrested by Soviet authorities after an unrelated violent incident. His espionage remained undiscovered at first, but he was later convicted of treason and executed in 1985.^[3]

7 Operation Tamarisk

Some Cold War agents relied on hidden cameras, miniature transmitters, and elaborate disguises. The operatives involved in Operation Tamarisk relied on gloves, plastic bags, and a willingness to search through Soviet garbage.

Western military liaison missions were officially stationed in East Germany to maintain contact with Soviet forces, but they also gathered intelligence whenever opportunities arose. British, American, and French personnel followed Soviet military exercises, photographed equipment, and searched abandoned encampments for anything soldiers had discarded.

Paper was often scarce among Soviet troops, so classified documents, training notes, and military manuals sometimes ended up being used as toilet paper. Because the paper did not dissolve, Western agents could retrieve it from makeshift latrines and piece the fragments together. Other searches uncovered discarded documents containing information about weapons, military exercises, unit morale, and new Soviet equipment. The unpleasant practice became known as “tamarisking” and turned what looked like worthless refuse into a surprisingly productive source of intelligence.^[4]

6 Operation Solo

Operation Solo began with an unlikely pair of agents: Morris and Jack Childs, two brothers who had spent much of their lives inside the American communist movement. Morris had once held an influential position in the Communist Party USA, but poor health and an internal power struggle pushed him out of the organization. The FBI later persuaded both brothers to become informants.

With the bureau’s assistance, Morris restored his health and rebuilt his standing in the party. By 1958, he had become a trusted courier between American communist leaders and officials in Moscow and Beijing. His access allowed him to meet senior communist figures, carry messages, and transport Soviet financial support—all while secretly reporting to the FBI.

For nearly two decades, the brothers supplied information about Soviet intentions, communist finances, international party disputes, and the growing division between the Soviet Union and China. Every trip carried the risk that Morris would be searched, followed, or exposed by someone who remembered his earlier fall from favor. Operation Solo officially ended in 1977 without the Soviet Union discovering that one of its trusted American contacts had been reporting to the FBI.^[5]

5 The Hunt for Aldrich Ames

Aldrich Ames spent his career searching for Soviet spies inside the United States. Unfortunately for the CIA, he eventually became one himself. Ames joined the agency in 1962 and specialized in Soviet intelligence operations, giving him access to some of America’s most sensitive secrets.

In April 1985, Ames secretly approached officials at the Soviet embassy in Washington, D.C., and offered them classified information. He was soon paid $50,000 and began identifying Soviet officials who had been recruited by the CIA and FBI. His betrayal compromised more than 100 American intelligence operations and contributed to the deaths of 10 American assets.

The CIA knew it had a mole but struggled to find him. Ames’s extravagant spending eventually attracted attention because his lifestyle far exceeded his government salary. The FBI opened an investigation in 1993, placing him under intensive physical and electronic surveillance. Agents watched him leave signals for his Russian handlers and followed him to a meeting in Bogotá. Ames and his wife were arrested in February 1994, ending a betrayal that had lasted nearly a decade.^[6]

4 The U-2 Spy Plane Incident

On May 1, 1960, CIA pilot Francis Gary Powers took off in a U-2 reconnaissance aircraft for a secret flight across the Soviet Union. His mission was to photograph military facilities before landing in Norway. The operation came only days before an important summit in Paris, where American and Soviet leaders were supposed to discuss nuclear weapons and worsening Cold War tensions.

The U-2 could fly above 70,000 feet (21,336 meters). Although Soviet radar could detect it, American officials believed it flew beyond the effective reach of Soviet interceptors and surface-to-air missiles. That assumption ended when a Soviet missile struck Powers’s aircraft near Sverdlovsk. He survived his parachute descent and was captured along with the plane’s camera equipment.

The United States initially announced that a civilian weather aircraft had disappeared after its pilot experienced problems with his oxygen equipment. Soviet leader Nikita Khrushchev waited until the cover story had been released before revealing that Powers was alive and in Soviet custody. President Dwight D. Eisenhower acknowledged the espionage mission, but he refused to apologize for it. The Paris summit collapsed, and Powers was later exchanged for Soviet spy Rudolf Abel in 1962.^[7]

3 Operation RYAN

In 1981, Soviet intelligence services began Operation RYAN, an enormous effort to detect preparations for a surprise American nuclear attack. Its name came from a Russian acronym meaning “nuclear missile attack.” KGB and military intelligence officers stationed around the world were ordered to watch the United States and its allies for signs that a first strike was approaching.

Some of the supposed warning signs were surprisingly ordinary. Agents monitored government buildings for unusual nighttime activity, watched the movements of senior political and military leaders, and looked for changes in blood supplies, civil defense preparations, and communications. The problem was that these indicators could make routine Western activity appear threatening.

The danger became particularly severe during Able Archer 83, a NATO exercise simulating the escalation from conventional fighting to nuclear war. Soviet leaders feared the exercise might be disguising preparations for a real attack, while Operation RYAN encouraged intelligence officers to search for evidence supporting that fear. Soviet forces took unusual precautions, increasing the risk that a training exercise or misunderstood signal could produce a genuine confrontation between the nuclear powers.^[8]

2 Operation Ivy Bells

During the early 1970s, the United States learned that a Soviet underwater communications cable connected major naval facilities in the Sea of Okhotsk. Because the Soviet government considered the sea secure, many of the conversations carried by the cable were not heavily encrypted. The problem was reaching it without being discovered.

The nuclear-powered submarine USS Halibut secretly entered Soviet-controlled waters and searched the seafloor for the cable. Divers then left the submarine hundreds of feet below the surface and installed a listening device around it. The equipment did not cut or penetrate the cable, making its presence difficult to detect. It recorded communications that American intelligence agencies later collected and analyzed.

For years, submarines returned to retrieve recordings and maintain the equipment. The operation provided information about Soviet naval activities and weapons while requiring American crews to work deep inside waters patrolled by enemy ships. The operation ended after former National Security Agency employee Ronald Pelton sold information about it to the Soviet Union. Soviet forces eventually located and removed the device, ending one of the Cold War’s most daring eavesdropping operations.^[9]

1 Project Azorian

In 1968, the Soviet ballistic-missile submarine K-129 disappeared in the Pacific Ocean with its entire crew. Soviet forces searched extensively but could not locate the wreck. The United States eventually found it approximately 1,800 miles (2,897 kilometers) northwest of Hawaii, resting around 16,500 feet (5,029 meters) beneath the surface.

Recovering the submarine could give the United States access to Soviet missiles, codebooks, communications equipment, and other intelligence. However, no ship existed that could secretly lift such a massive object from more than 3 miles (4.8 kilometers) underwater. The CIA therefore built one. The Hughes Glomar Explorer was publicly presented as a commercial vessel designed by billionaire Howard Hughes to mine manganese nodules from the seafloor. Its real purpose was to lower an enormous mechanical claw around the wreck and pull it into a concealed compartment.

In 1974, the ship began the recovery while Soviet vessels watched from nearby. The cover story held, but part of the submarine broke away during the lift and plunged back to the ocean floor. The CIA still recovered a portion of the wreck, including the bodies of six Soviet sailors, who were given a formal burial at sea. Although the mission achieved only part of its objective, the fact that the CIA had designed and operated an enormous ship to steal a submarine from beneath Soviet surveillance made Project Azorian one of the most audacious espionage operations of the Cold War.^[10]