Quite probably the largest, coolest, and most under-rated library in the world.
The Internet Archive’s Wayback Machine is a digital archive of the entire internet, and enables any and everybody to travel back through digital time and look at what websites have looked like at different moments in the world wide web's history.
The Internet Archive (Archive.org)Â was founded by Brewster Kahle and started archiving the web in 1996 and has saved nearly a trillion web pages since then and now probably has more valuable data about the internet and users than any other company in the world and, admirably, they refuse to collect or sell user data despite pressure from many people to do so. They can take this independent stance because the organization is funded entirely by grants, donations, and partnerships.
In addition to web pages, they also archive video, software, music, and even have a growing archive for television. That's rather prescient because many TV networks don’t keep their old content so this is the only place you can find it.
The Internet Archive also operates out of a physical building in, as you might suspect, San Francisco. It's an old Christian Science church, and they bought it because it looked like their logo. They still have the pews, organ, stained glass windows and many other remnants from the church. If you're in town, you can even book up for a free tour on any Friday.
The company hosts all of the data themselves, and they even have physical servers in the SF location - but they also have backups of the data in various locations around the world.
Without the endeavours of the Internet Archive, it is highly likely that one of the most transformative technologies in history would be lost with time. That may not seem like a big deal, but in a sense, they’re one of the few defensive forces against the many actors who may want various parts of the web to disappear for one reason or another. If you would like to support the organisation's work, you can donate here.