It’s official: I’ve registered for the 3-Länder-Marathon, which takes place this October at Lake Constance. And I want to tell you why I think you should consider it too. 🌍 Three Countries, One Race The name says it all: 3-Länder-Marathon literally means Three Countries Marathon. And that’s exactly what it is. You start in Lindau, Germany, run through Austria, into Switzerland, and…