Astrid, City of Purity

When this land enters the battlefield, pay 2 life
or sacrifice it.
{t}: Add {b} or {w} to your mana pool. If you
control two or more Castles, add one mana of any
color to your mana pool instead.
{1}, {t}: Add one mana of any color to your mana
pool.
"This city may look pretty on the outside, but it'll take
a piece of you with it."