Internet Explorer is a graphical web browser developed by Microsoft that was included in Windows operating systems starting in 1995. It was the default browser until being replaced by Microsoft Edge in Windows 10, though it remains available. It was initially based on Spyglass Mosaic and helped popularize web browsing. Internet Explorer supported early web standards and introduced features like security zones and group policy configuration. Major versions added functionality like HTML5 support and performance improvements. While free and widely used, it also had bugs, security issues, and lacked features of other browsers.