Underwater explorers think they might have discovered treasure which used to belong to the notorious pirate Captain Kidd.
A large silver bar with markings on it was found by American explorer Barry Clifford, who was scuba diving in Madagascar.
He had an underwater metal detector with him, and found the silver bar in the wreck of what he thinks could be Captain Kidd's old pirate ship.
The location of the ship, thought to have sunk in 1698, has been known about for many years, but the silver bar was only discovered earlier this week.
A few people aren't sure if the bar really did belong to the pirate, and are calling for more proof.
If the treasure is proved to be genuine, it would mean that the silver bar is more than 300 years old, and that the legendary lost treasure of Captain Kidd has been found.
Barry thinks there might be more silver bars in the wreck, but said it was too muddy for him to see anything.
Who was Captain Kidd?
It is thought the famous pirate was born in Scotland around 1645.
Captain Kidd was appointed by the Crown to help fight against piracy, but he ended up becoming a pirate instead!
After a few years of piracy Captain Kidd was finally captured and brought back to London in 1701 to be punished for his crimes.
Legend had it that Captain Kidd hid much of his loot, which has led to numerous treasure hunts around the world, and inspired the author who wrote Treasure Island.