How to change window url without redirection or reloading of page?

When I click on "Liked By" below an instagram post, it shows a popup of the list of people who liked that post. Somehow, it also changes the url from www.instagram.com to www.instagram.com/p/<some random alphanumeric text here>/liked_by/. As you see, the url has changed without the page being reloaded and there is no # in there either. How is this done?

I've a .NET background but I'm not up to date on the latest web technologies and this question is technology agnostic because I don't know what technology instagram uses but feel free to point me in the right direction and I'll research the .NET equivalent of what's going on.