Bariloche is a sizable city, but most of its Nazi attractions are within a few-block radius, including Priebke’s Colegio Aleman, also known as Primo Capraro, and other German cultural institutions. April 20 wasn’t just Easter—it was Adolf Hitler’s birthday, his 125th, in fact. The journalist Abel Basti, who has written a controversial book claiming that Hitler escaped to Bariloche and lived here for decades, told me the birthday parties used to be held at a hotel downtown but have moved to obscure estates in the years since Priebke’s arrest. Basti, who has also written tour guides to Bariloche’s Nazi sights,...