LightGallery is a popular JavaScript library designed for creating responsive image and video galleries on websites. It allows users to display media in a visually appealing way, offering features like zoom, fullscreen mode, and touch support for mobile devices. The library is easy to integrate and customize, making it suitable for both beginners and experienced developers. With support for various media types, including YouTube and Vimeo videos, LightGallery enhances user experience by providing smooth transitions and a clean interface for viewing content.