Imperial Citadel

Imperial Citadel enters the battlefield tapped.
{t}: Add {w} to your mana pool.
{t}, Pay 1 life: Add {u} or {b} to your mana pool.
{3}{w}{u}{b}, {t}, Sacrifice Imperial Citadel: You draw a card and gain 2 life. Each opponent discards a card and loses 2 life. Activate this ability only any time you could cast a sorcery.