123abc.zip is a release file of the Minecraft map Muckcraft, made for Minecraft 1.6.2. It was published on September 24, 2013 and is 2.9 MB in size. For the full description, screenshots and every other version, visit the Muckcraft map page.
How to install: Extract the .zip and move the world folder into .minecraft/saves; the map then appears in your Singleplayer list.
