Since the dawn of time, people have been obsessed with sex. The earliest depiction of people doing it - that we know of - comes from near Bethlehem and was made about 11,000 years ago. It's a sexy stone sculpture. Any art form you can name, you can find with erotic subject matter. Pottery? Frescoes? Mosaics? Temple walls? Porn has been around for millennia. As technology evolved, so did the ways porn could be distributed. Early printing presses really helped get horny pics into the hands of horny people. Photography completely changed the game, and mass produced "French Postcards" - pics of naked ladies - circulated throughout the world in the 19th century. "Tijuana Bibles" - smutty comics - were popular in America in the 1920's. Porno mags, WW2 pinups, PornHub! Over time, the delivery systems for erotica has changed, but people's appetite for sexy imagery remains the same.