Global Ruin | Magic: The Gathering
Formats Global Ruin is Legal in
Official Oracle Text for Global Ruin
Official Rulings for Global Ruin
8/15/2010 : You sacrifice all lands other than the chosen ones. Since you can only choose lands with basic land types, any non-basic lands that don't have a basic land type (even if they have some other land type, as in the case of Cloudpost) are necessarily going to be sacrificed.