On 17 September 1991 Linus Torvalds uploaded Linux kernel version 0.01 to a FTP in the University of Helsinki. It counted a bit more than 10.000 lines of code.
At that time, he didn't realize what that shy gesture will mean, since nowadays Linux runs inside a lot of devices we use dialy, such as browsers, smartphones, routers and even intelligent objects.
Torvalds based his development on Minix GNU C compiler and it took him about 12 minutes compiling the code, which was only 62Kb.
24 years later, 4.2 version has been released and only in this latest version more than a million lines of code have been added, thanks to the developer community contributing to the project.
In order to celebrate Linux 24th birthday, here you are a video by The Linux Foundation about How Linux is built