Sunscreen was invented for soldiers, not beach-goers

The first modern sunscreen was developed in 1944 by airman Benjamin Green, who mixed red petrolatum (a by-product of oil refining) with cocoa butter to protect US soldiers in the Pacific theatre from intense tropical UV radiation. He tested it on his own head. After the war, Coppertone bought the formula and commercialised it with a higher-SPF formulation and a brown tan-girl mascot. The original UV-blocking compounds used were benzophenones, now controversial due to absorption into the bloodstream; mineral-based zinc oxide and titanium dioxide sunscreens, physically blocking UV, are now considered safer alternatives.

Source: Shaath, Sunscreens: Regulations and Commercial Development (2005)