We've covered a number of Wikipedia Diver may be one of the most interesting, albeit niche. This Firefox add-on gives you a visual history of everywhere you've been on Wikipedia, and organizes it down to the day, order, and session in which you visited the sites, making it easy to revisit old entries.and in the past, but
Each visited page is presented as a small red globe that you can click on to advance the timeline. There's also a source list of every site you visited, that will take you right to the page.
Like some other Web history trackers, Wikipedia Diver intelligently tracks when you hit the back button on your browser. Each time you leave whatever Wikipedia entry you're on to visit a link that's on that page, it simply attaches it to your history. In one entry I was looking at, I had clicked on seven different links that were on that page, and the extension kept track of how I had arrived at each of those pages. That in itself can be fun to look at--e.g. how I got from the Zoopraxiscope to the assassination of Alfred Herrhausen.
One thing it does not track are the reference links you click when exiting the site to view a source. I'd like to see this added as an option, but understandably that takes it into the realm of watching everything you do.
Also worth a mention is that all of this data is kept safe and secure on your local machine, and never sent to the cloud. Like any other extension that does this, this means that your information isn't being beamed elsewhere, although you can only access your history on that particular machine, and in that particular browser.