The human terrain skewed elderly, stout and wurst-colored; the area was crowded despite an inhospitable chill that few American beachgoers would suffer through. Near the spot where my husband and I plopped down — in our bathing suits, for now — a married couple (aubergine-haired woman; uncircumcised man) began the afternoon collaborating on a crossword puzzle. He fell asleep in the sand — prone, splayed like a starfish — and she woke him up by prodding his gut with a foam noodle. Together they wandered into the bracing ocean, dove in and remained in the 50-degree water for over an hour. Nearby, a naked mother and her naked teenage daughter each ate two apples apiece, burying the cores beneath lumps of kelp. Some bathers appeared appropriately outfitted for the gusty climate and came equipped with nylon half-tents, which, when pitched perpendicular to the shore, provided wind protection but no privacy at all. Most others, though, seemed unperturbed by the weather.

Those who were not swimming lay perfectly still, holding themselves steady not in pursuit of a golden complexion but in homage to some antiquated notion of fitness. Germans, known to credit oddly specific activities with salubrious effects (e.g. walking barefoot through damp grass), retain an atavistic faith in the advantages of full-body sun exposure, which was prescribed to tuberculosis patients in the late 19th century. “Of course it’s more healthy when it’s 15 degrees out not to have a suit,” a German musician told me, waving his hand with impatience.

NACKTKULTUR, THE OTHER TERM by which Freikörperkultur once went, has a disputed etymology. Some allege it dates back to the natural healing movements of the late 19th century; others claim it was coined around 1900 by Heinrich Pudor, an author whose early books promoted a vegetarian, nudist lifestyle, and whose later work was almost exclusively anti-Semitic. Well into the 20th century, outdoor nudity was thought to cure respiratory illnesses. Membership in early German nudist clubs — there were over 200 of them — was evenly split between men and women, and by the end of the 1920s, there were almost as many books published on the subject as there were about sports and dance.

Adolf Koch, a former schoolteacher who believed in nudity’s pedagogical benefits, founded a network of nudist schools, and in 1929, the Berlin campus hosted the first International Congress on Nudity. FKK groups were initially banned by the Nazis, but the practice soon returned and was wanly tolerated throughout the Third Reich. When authorities began to patrol Baltic beaches in the 1950s to prohibit nudity, there was an outcry — and many protests.