Call of Duty: Modern Warfare 3 Easter Egg - Cthulhu Ale

Choose the MW3 map Lockdown. Starting from the Gallows, head to the right through the archway with the four statues in it. Turn left and follow along the walkway to the first closed door on your left surrounded by the reddish wood. On the left wall of that alcove is an ad for "La Cthulhu Verte: Abs!nthe Fhtagn!"

A clear reference from the books by H.P. Lovecraft.