Where is the black market in the world of magic?

In the world of magic, the black market often operates in hidden, underground venues where illicit magical goods and services are traded. This may include enchanted artifacts, forbidden spells, or even magical creatures. Major cities with vibrant magical communities, like Diagon Alley in London or various hidden markets in New York, may have clandestine sections where these illegal transactions take place. Such markets are frequented by rogue wizards, desperate individuals, and those seeking power outside the law.