Raspbian is a GNU/Linux operating system specially designed and optimised for Raspberry Pi.
You can download latest Raspbian version on this page.

Raspbian Jessie

The latest version of the full Raspbian OS, rather adapted to Raspberry Pi 2 and Raspberry Pi 3
SHA-1: c35688583510fc93c5deac637976b7a5c9c55689

Raspbian Jessie Lite

You can download a smaller version of Raspbian, rather adapted to Raspberry Pi A+ or Raspberry Pi Zero
SHA-1 : 91467f778f5374613dbb3c5c68c20682b4817a3c
Download in progress...
While downloading your file, you could do a coffe and drink it by reading our article on the choice of Raspberry Pi accessories