The Ice Arena is construction site bought from the shop, introduced in the update on 05.21.2013. It can be placed anywhere in the playable game area. It can be upgraded two levels, all granting a higher increase to the Population Cap.
As with all construction projects, there is a choice between waiting, and receiving gifts via neighbors, or buying any/all required assets with megabucks . A total of 50 assets are needed to complete construction of the Ice Arena to level two; this equates to 50 if you were to buy every asset.