Basilisk II is an Open Source 680×0 Macintosh emulator developed by Christian Bauer. That is, it enables you to run 68k MacOS software on your computer, even if you are using a different operating system. However, you still need a copy of MacOS and a Macintosh ROM image to use this program. Basilisk II is distributed under the terms of the GNU General Public License (GPL).
Thanks to EvilDragon for the news.