City of Tears

({t}: Add {u} or {b} to your mana pool.)
As City of Tears enters the battlefield, you may
pay 2 life. If you don't, City of Tears enters the battlefield tapped.
The city looks to be built into an enormous cavern,
and the rain pours down from cracks in the stone
above. There must be a lot of water up there
somewhere.
—Quirrel