Boulangerie Chari in Brussels, Belgium has the second best almond croissants the world over; the best can be found herein. Hands down. And I'm a connoisseur of this particular food, as it's my dietary Achilles heel.
Also of note are: all their other pastries. I asked, and they can't ship to the united states. BUT, they're worth bribing your friends to bring em home for you. Oh yes they are!