Here you can download the official Mac OS X 10.0 Cheetah ISO for free.
Mac OS X 10.0 (code named Cheetah) is the first major release of Mac OS X, Apple’s desktop and server operating system. It was released on March 24, 2001, for a price of $129 after a public beta.
Mac OS X was Apple’s successor to the classic Mac OS. It was derived from NeXTSTEP and FreeBSD, and featured a new user interface called Aqua, as well as improved stability and security due to its new Unix foundations. It introduced the Quartz graphics rendering engine for hardware-accelerated animations. Many technologies were ported from the classic Mac OS, including Sherlock and the QuickTime framework. The core components of Mac OS X were open sourced as Darwin.
Boxed releases of Mac OS X 10.0 also included a copy of Mac OS 9.1, which can be installed alongside Mac OS X 10.0, through the means of dual booting (which meant that reboots are required for switching between the two OSes). This was important for compatibility reasons; while many Mac OS 9 applications could be run under Mac OS X in the Classic environment, some, such as applications that directly accessed hardware, could only run under Mac OS 9.
Download Mac OS X 10.0 Cheetah:
Architecture: PowerPC
File-Format: ISO
Download: Archive.org