City of Solitude

Enchantment

Players can cast spells and activate abilities only during their own turns.

"My horizon was the arcing petals, my new home resplendent with spires of weeds and pillows of fragrant pollen."
—Naimah, Femeref philosopher

2004-10-04 City of Solitude can affect abilities of cards that are not on the battlefield because it prevents players from activating those abilities.
2004-10-04 City of Solitude does not stop triggered abilities from being put on the stack. They are never "activated".
2009-10-01 This stops players from activating mana abilities.

Card is in preconstructed decks:

mtg.wtf