Arcadia.zip is a release file of the Minecraft map Arcadian Islands, made for Minecraft 1.12.1, 1.12.2. It was published on November 28, 2023 and is 189.5 MB in size. For the full description, screenshots and every other version, visit the Arcadian Islands map page.
How to install: Extract the .zip and move the world folder into .minecraft/saves; the map then appears in your Singleplayer list.