“Those look tempting.” Alex Peterson, a lanky blond 19-year-old from Salt Lake City, pointed toward a bloc of gray apartment buildings nestled on a hill in Pristina, the capital city of Kosovo. It was a Friday morning in July. Peterson and his colleague Tanner Racine, from Idaho and also 19, entered one of the concrete buildings and walked up several flights of stairs to the top floor. Choosing a door in a dark hallway, the young men knocked. No answer. “A lot of the time, it’s a waiting game,” Peterson said with a shrug. Just then, a man stepped outside an apartment across the hall. Peterson and Racine greeted him in practiced Albanian, the local language. They pointed to their name-tags—“Elder...