Shields can be earned and collected from bingo rounds. This will protect your Land from a single attack from other players. You can hold up to 3 Shields at a time - that will protect you from 3 separate attacks.
Your Land can be attacked at any moment so make sure you have Shields to protect your Land while you're away! When a player successfully attacks your Land's Monuments, you'll need to repair it with your Monument Points - this can slow you down from advancing to the next Land in the Bingoverse!
If you don't have any Monuments built on your Land or if if all your Monuments are destroyed down to the lowest tier, players can attack your Monument Points directly! This means that your accumulated Monument Points will be taken by the attacking Players. Make sure to get those Shields!