Kumungu Jungle

Kumungu Jungle enters the battlefield tapped unless you control only Forest lands.
When this land enters the battlefield, return a land you control to its owner's hand.
{t}: add {g}{g} to your mana pool.
Few dwellers are residing in the blasted and dangerous lands that lie south of the Great Barrier. There are long-forgotten treasures in these strange places which many risk life and limb to acquire.