Caucasus oil fields

Your opponent can choose to attack Caucasus oil fields. If all creatures defending Caucasus oil fields are destroyed or put in to exile or if you do not defend Caucasus oil fields your opponent gains control Caucasus oil fields. Creatures which are controlled by the player that controls the copy of Stalingrad that put Caucasus oil fields in to the battlefield have +1/0 when attacking or defending Caucasus oil fields.
Artifact creatures you control have vigilance.
{t}: Add {3} to your mana pool.