To celebrate the 50 year mark since the first public Danish porn expo, porn site xHamster created an interactive calendar of sex history. And while you might think the calendar is a repository of your own viewing history, it most certainly is not.

Instead, it’s filled with sexual milestones in history, including when The Institute for Sexology opened in Berlin (July 6, 1919), when Viagra hit the market (March 27, 1988), and each country’s legalization of same-sex marriage since the turn of the millennia.

The Danish were the first in the world to legalize hardcore pornography (July 1, 1969), and Sex 69 was the first public event that brought together porn producers without threat of arrest. We won’t ruin all the hidden factoids though, you can explore for yourself instead.

Founded April 12 in 2007, xHamster now has over 2 billion viewers each year. Vice president Alex Hawkins says “without Sex 69, xHamster would never exist.” He declared October 21 be World Porn Pride day. “We must remember these milestones in sexual liberation, because our history is vital and important.”

Though there’s almost 100 dates logged in the calendar already, xHamster says it is looking to build on it as time goes on, requesting the public to suggest other dates in history. It’ll also eventually list upcoming events.

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