Arcane Sanctum
Land
Oracle Text
This land enters tapped.
{T}: Add {W}, {U}, or {B}.
Watch Out
Mana abilities don't use the stackRules Note
If this card's activated ability produces mana and doesn't target, it's a mana ability. Mana abilities resolve immediately without using the stack — opponents can't respond to them. However, abilities that target (even if they produce mana) aren't mana abilities.