Bolas's Citadel

You may look at the top card of your library any time.

You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its
mana value rather than pay its mana cost.

{t}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

The Capital City, located at the foot of the Erdtree. Despite being partially destroyed by the dragon Gransax, it still holds strong to this day.