While you might think that CityVille should have already started on its Valentine's Day celebration (hey, FarmVille's already doing it), we're instead given a new feature dealing solely with winter: The Winter Castle. This Winter Castle is available to users level 30 and above, and comes via a goal called "Castle in the Snow." This one asks you to place and complete the Castle, collect from an Ice Tower three times and collect from 20 Winter-themed businesses.
Since that's a lot going on, let's tackle things one by one. The Winter Castle is an upgradeable building that requires you to collect building parts to upgrade. After spending 12 energy to build the frame, you'll have to collect 35 materials to just finish the base Castle:
7 Ice Blocks
7 Ice Trees
7 Ice Shingles
7 Ice Tools
7 Ice Weather Vanes