For 50 years Swiss observers have been stationed on the demarcation line between North and South Korea, one of the world's most heavily fortified borders.
Sandwiched between more than 1.5 million troops, their mission is a peculiar mix of diplomacy, continuity and ritual.
"In the 1950s, Switzerland's role was far more hands-on," Major-General Adrien Evéquoz, who commands the Swiss Observer Mission, told swissinfo.
"Our predecessors used to carry out inspections of the number of troops and weapons that were entering the area.
"Now, our job is simply to support the peace structure and show the North and South Koreans that the mechanisms of the armistice agreement are still in place," he explains.
Headquartered in Panmunjom, right on the edge of the meandering line marking where the fighting between the two Koreas ceased, the five-strong mission's function is to ensure the 1953 armistice agreement is adhered to.
The most visible demonstration of this commitment to peace is a ritual carried out every Tuesday morning.
This is when one of the observers walks from the Swiss camp through a gate in the protective metal fencing and barbed wire, and crosses a wooden footbridge. The bridge is painted sky-blue, the colour of the United Nations flag.
"It's symbolic. We go at 10am sharp to show the North Koreans that we take our mission seriously," says Evéquoz's deputy, Colonel Christian Studer.
A short walk takes Studer or one of his colleagues to what is known as "Conference Row". It is a set of huts straddling the demarcation line between North and South Korea.
Built mainly for holding meetings, the huts are part of the Joint Security Area - a tiny "island" within the far larger (241km by 4km) Demilitarised Zone (DMZ).
There, the Swiss will exchanges observations with a Swedish military delegation, whose role is similar to that of Switzerland's observer mission.
Studer says that they often have little to tell each other in terms of new developments. "But a failure by the delegates to turn up on a Tuesday morning might indicate to the North Koreans that something was amiss," he adds.
Cold War divide
Switzerland and Sweden are members of the Neutral Nations Supervisory Commission (NNSC). Established in 1953, it used to comprise Czechoslovakia and Poland as well.
The four countries were mandated to supervise, inspect, observe and investigate activities outside the DMZ.
However, with the end of the Cold War, the North Koreans forced the delegations from the former Eastern bloc to withdraw from the northern side of the DMZ, and Pyongyang ceased its cooperation with the NNSC.
Now just the Swiss and the Swedes are left, living out a surprisingly laid-back day-to-day existence.
To access the camp, an armed United States military escort is needed to get through the heavily fortified and mined defences of the southern boundary of the DMZ.
There are three main checkpoints, manned by US and South Korean soldiers who are armed to the teeth.
But once inside the Swiss camp, there are no weapons in sight and hardly a sound is to be heard.
Set amid the pine and fir trees that make up the verdant backdrop for the observers' living quarters, cross-border tensions seem very distant.
The stillness is punctuated only by propaganda music emanating from distant loudspeakers that both the North and South Koreans have hoisted along the border.
"I offered to come to Panmunjom because I had heard it would be far more relaxed than other missions I have been on," says Studer, as the officers relax back in the camp clubhouse.
"In Sarajevo and Beirut, life was dangerous. Here, everything is relaxed and calm."
swissinfo, Juliet Linley in Panmunjom
Calmy-Rey's ten-day trip will take her to North and South Korea and China.
On Tuesday she will become the first foreign government official to cross the demarcation line between North and South Korea.
Swiss personnel have been stationed at Panmunjom as part of the Neutral Nations Supervisory Commission in Korea (NNSC) since 1953.
Calmy-Rey met her North Korean counterpart paek Nam Sun on Monday.