Sweden.
Esrange Space Center (short form Esrange) is a rocket range and research centre located in northern Sweden. It is a base for scientific research with high altitude balloons, investigation of the aurora borealis, sounding rocket launches, and satellite tracking, among other things. Esrange, built 1964, is located 200 km north of the Arctic Circle and surrounded by a vast wilderness, its geographic location is ideal for many of these purposes.
Esrange is surrounded by hundreds of kilometers of forest, mountains and marsh, and is very far from the nearest settlement. By luck, or extreme coincidence, but in early spring 1979 a body of a dead man was found about 10 kilometers north of Esrange, wearing only a smoking(!). -30°C is not unusual at this location, and smoking is probably so far from the right clothing you can go.
Newspapers in Sweden, Norway and Finland wrote about it, but no one came forward and missed a man in the 30s, and still nobody knows who the smoking dressed man in the wilderness was. He is buried in a nameless grave by the church of Kiruna since 1979.
Esrange Space center, Sweden
Esrange Space center, Sweden