The seaside resort was where the serious healing took place. The sea air along with the ocean views and warm weather were considered critical to a patient’s recovery, especially when treating tuberculosis. But dunking yourself in the water until you nearly drown only takes a few minutes. With treatment plans lasting weeks and even months, the captive patients required additional treatments and plenty of entertainment to pass the time. First appearing up and down the British coast and then spreading to the Continent, seaside resorts offered a kind of holistic self-improvement retreat where the mind, body and soul were treated simultaneously and with equal attention. Horseback riding purged bad air, sailing calmed the nerves, dancing and dinners promoted social connections, and geologically themed beach excursions stimulated the intellect.

But bodily healing was the main event, and patients believed that their own scientific observations played a critical role. Patients kept personal logs of their progress, and detailed their physiological responses to sea therapies from their bowel movements to their circulation. The sea resort remained popular for treating tuberculosis until the epidemic finally abated in the 1860s, despite the fact that there was no real proof of its success.

As seaside resorts popped up all over Europe and the U.S., they became less about therapy and more about entertainment. By 1911 there were more than 100 seaside resorts in England and Wales alone, according to The English Seaside Resort: A Social History. With better roads and train transport, the masses rolled in and the elite rolled out—seeking their fresh air fix in the country away from the riff raff. But having exploited its water and air, there was one more element of the beach that the medical establishment had not yet seized upon: the sun.

Until the 1920s, people went to the beach in spite of the sun. Ladies would bundle up and shade themselves under umbrellas and canopies to shield their alabaster skin from the toasting effects of the sun’s rays. The aristocracy thought dark skin was for peasants and natives who had neither the elegance nor the privilege to live a life indoors, according to Lenček and Bosker. The sundrenched parts of the world were home to the great fallen civilizations of history like the Phoenicians, Greeks and Romans. Clearly, the sun loosened morals and melted minds. Then the Germans got naked and changed everything.

By the end of World War I, the Western World saw sun-loving civilizations that were once cautionary tales of vice, such as the Greeks, Romans, and Mayans, as healthy and pure. In Germany, the free body-culture movement, Freikörperkultur, promoted nudism and a new respect for the body unfettered by society’s constraints. Being healthy meant displaying a body that emanated the very glow of nature—the sun. Everyone from the avant-garde artists of Weimar to Hitler embraced the ideal of the robust, sun-kissed body. Tanned skin became the height of chic, embodying the opposite class distinction that it had during the previous century. And, it joined seawater and sea air as the panacea du jour. In 1944 The Journal of the American Medical Association promoted the sun, air and sea trifecta as a cure for everything from tuberculosis (still) to a cold. Companies capitalized on the sun's appeal by promoting contraptions like a personal hothouse that captured “health rays” right out of your backyard.