From petticoats to Spanx, underwear is the oldest garment known to humankind. “Delicates,” as they’ve been known, have had many variations and come with a secret history that many don’t know about. (For instance, did you know that Mark Twain invented the bra clasp? It’s true.) Here’s a cute little infographic that charts the evolution of women’s underwear because let’s face it, women’s underwear is more interesting than men’s.