In August 1961 the Allies had failed to prevent the building of the Berlin Wall and although they quickly condemned it, they were not prepared to go to war over Berlin.
It is recorded that President Kennedy said, "A wall is a hell of a lot better than a war."
However, the Allies in Berlin were determined to maintain their agreed right of access to East Berlin and along the road/rail/air routes between West Berlin and West Germany.
At the end of August 1961, in a direct response to the harassment of Allied personnel travelling to Berlin and the Soviet threat concerning the freedom of the air corridors, Kennedy made a public show of ordering 148,000 National Guardsmen and Reservists to active duty.
During October 1961, East German officials began to deny US diplomats the unhindered access to East Berlin that was part of the agreement with Moscow on the postwar occupation of Germany.
Checkpoint Charlie is the crossing point for the Allies through the Berlin Wall into East Berlin
The picture shows the events of August 1961 when the Berlin Wall was erected
Note: Checkpoint Charlie is so named, being the third Allied crossing point......Checkpoints Alpha & Bravo were at either end of the road corridor from West Germany to Berlin
On the 22nd October, a senior US diplomat in West Berlin was stopped by East German border guards on his way to the state opera house in East Berlin.
The East Germans demanded to see his passport but the US diplomat insisted only Soviet officials had the right to check.
The diplomat was forced to turn back.
In a similar scene to this image, the car of the US diplomat was approached by East Germans who demanded to see his documentation
General Lucius D. Clay had been sent by Washington to deal with the Russians after the erection of the Berlin Wall and he ordered that the next American diplomat entering East Berlin was to be escorted by armed US army military police in jeeps.
A US diplomatic car is escorted into East Berlin by American jeeps
The manoeuvre succeeded but the East Germans continued to claim control over western allied officials crossing between East & West Berlin and they hindered diplomatic crossings.
A US diplomatic car is prevented from leaving East Berlin.........US jeeps go to extract the diplomats.
On the night of the 27th October, General Clay ordered ten American M48 tanks to head for Checkpoint Charlie.
They parked, some 50 metres from the border, noisily racing their engines and sending plumes of black smoke into the night air.
Alarmed by the apparent threat, the Soviets sent an equal number of their T55 tanks to face down the Americans.
They too ground to a halt some 50 metres from the East / West Berlin border and faced the US armour for 16 hours.
US and Soviet tanks face each other across Checkpoint Charlie
A wrong move during the face-off could have led to war and General Clay was reminded by Washington that Berlin was not "so vital” an interest to be worth risking a conflict with Moscow.
Kennedy made use of back channels to suggest that Khrushchev remove his tanks, promising that if the Soviet Union did so, the U.S. Army would reciprocate.
At 11am on the 28th October a Soviet tank reversed some 5 metres and this was followed by a similar US tank movement.
With this staged withdrawal of tanks the standoff ended peacefully.
Following these events certain sections of the Berlin Wall were reinforced by the East Germans to be 'tank-proof'.
Building the 'anti-tank' Wall in front of the Brandenburg Gate
A 4:25min video detailing the standoff at Checkpoint Charlie