There is no doubt that the most well-known and infamous pirate of all time is Edward Teach, better known as Blackbeard. He terrorized the Caribbean for years before his eventual death in 1718. Three hundred years later, his massive, hidden fortune is still lost to history.
Despite how they're portrayed in pop culture, pirates did not leave maps laying around with an "x" marking the spot — probably because that's a terrible plan. If anything, they would know a general location and remember where it was buried. When it comes to massively successful pirates like Blackbeard, however, a single treasure chest buried six feet deep wouldn't be nearly enough.
In fact, as far as we know, only one pirate, Thomas Tew, used an actual treasure chest to stow his prize. That particular cache of wealth was valued at around $102 million in today's money. According to Blackbeard's ledger, his wealth was evaluated at a (comparatively) paltry $12.5 million. If you think that's suspiciously low for a pirate of his stature, you'd be correct. His ledger also notes that his real treasure "lay in a location known only to him and the devil."
In terms of a suitable hiding spot, it's more than likely stowed in a cave similar to Dungeon Rock in Massachusetts, where pirate Tom Veal hid his treasure. Knowing that Edward Teach often docked in the Carolinas, that'd be a logical start for treasure hunters. Ocracoke Island, North Carolina was his most common hang-out spot, but if it hasn't been found there over the last three hundred years, you can be sure it's not there.
Weeks before his death, Blackbeard knew his time was coming to an end. The Spanish and British were hot on his tail and, if he hadn't already, he wouldn't have had the time to consolidate all of his Caribbean treasures. He went down with his ship, Queen Anne's Revenge, off the coast of Ocracoke Island.
Many ships have been discovered off the shore, but none have identified as Queen Anne's Revenge. Although Blackbeard's ship was boarded, no Englishman was recorded as becoming extremely wealthy after the raid there's little reason to believe that there was a large sum of money on his ship.
As far as anyone knows, it's still out there somewhere...