WinHTTrack allows you to download a web site from the Internet to a local directory, building recursively all directories, getting HTML, images, and other files from the server to your computer. It is a free and open source website copier application that's easy-to-use and powerful.
Here are some screenshots to illustrate the features and user interface of this application:
Chromium Browser
Firefox Beta
Firefox Developer Edition
Firefox ESR
Yandex.Browser