There’s a lot of Internet Archive talk on here (shoutout MJ Lenderman) but i haven’t seen many people mention the Wayback Machine, which to me is far and away the sites coolest feature. You can just throw in any old URL and explore the early internet. Amazing web design and fantastic informational resource.
My favorite thing to do is look up the websites of old defunct bands. I’m linking to one of my favorites from Geoff Farina’s (Karate) band The Secret Stars, where he and his bandmate Jodi Buonanno chronicle their time spent renovating a 19th century Grange Hall into a recording studio/art space.