As specialty stand-in artwork, Google doodles serve as a sort of informal day calendar for the entire Internet. They are used to celebrate historical events, famous birthdays, groundbreaking inventions, and pretty much anything else deemed worth of replacing the search engine's ubiquitous logo for a day.

But when did this tradition start? What is the ur-doodle?

According to Google's official doodle history, the first one wasn't used to commemorate or celebrate anything, but rather serve as an "out of office" note.

In 1998, Google co-founders Larry Page and Sergey Brin were headed out to desert festival/spiritual quest/"thinkfluencer" summit Burning Man, and they wanted to playfully let site users know they were out of town. They re-did the company logo to include a Burning Man-inspired stick figure behind the second "o" (pictured above) and posted it on August 30.

The idea didn't return for another two years, when the two asked intern Dennis Hwang to design a doodle for Bastille Day. It was a hit, and soon Hwang became doodler-in-chief. Today, an entire team of graphic designers creates multiple doodles per day for use on Google's various international websites.