Andrew Stecklin, Alexandra Kiraly and Samantha Kiraly, all 9, tie knots like real pirates at the “Real Pirates” exhibition at the National Geographic Museum in Washington. (Marvin Joseph/The Washington Post)

Blackbeard and Calico Jack may seem like the stuff of legends, but a new exhibition shows that pirates and their treasures were real indeed.

Real Pirates,” which opened last week at the National Geographic Museum in Washington, tells the story of the Whydah (pronounced WID-ah), an 18th-century pirate ship that was discovered off the coast of Cape Cod, Massachusetts.

Underwater explorer Barry Clifford and a team of divers found the wreckage in 1984 and have brought more than 200,000 artifacts to the surface. One of the early finds — a bell with the word Whydah etched into it — proved that the wreckage was Sam Bellamy’s pirate ship. The artifacts are the world’s only verified pirate treasure.

The National Geographic exhibition features lots of the once-sunken treasure, including gold and silver coins. There are also pirate weapons: grenades, cannons and pistols.

“The oldest [coin on display] goes back to the time of Ferdinand and Isabella,” Clifford said, referring to Spain’s 15th-century king and queen.

The treasure chests are replicas, but the treasure is real, with some coins discovered in the Whydah dating back to the 15th century. (Marvin Joseph/The Washington Post)

But “Real Pirates” isn’t just about loot, it’s about a ship.

A short movie introduces the former slave ship, which became a pirate ship in February 1717, when Bellamy captured it near the Bahamas.

Visitors can see lots of everyday items — cups, buttons and pieces of clothing — that have been brought up from the wreckage. Those things may not seem exciting, but they have given historians a better understanding of what a pirate’s life was like.

Kids can test their pirate skills by tying knots and hoisting Jolly Rogers, or pirate flags. (Not all pirates were grown-ups. John King was only 9 when he joined the Whydah’s crew.)

Climbing aboard a re-created section of the ship is one of the most dramatic parts of the exhibition. The sounds of squeaking wood and howling wind greet visitors as they explore how Bellamy and his crew lived as they sailed the Atlantic, stealing from more than 50 ships.

The Whydah’s days of flying a Jolly Roger were numbered. On April 26, 1717, it sailed into a storm and sank, killing Bellamy and most of the crew.

When Clifford’s team discovered the wreckage, it was under 25 feet of water and up to 30 feet of sand. The exhibition’s final gallery shows how the artifacts are often found — covered in rock and hardened sand. The huge cost of digging up and cleaning the items has meant the recovery project has continued for almost 29 years.

For Clifford, the ship is his life’s work. He heard the Whydah’s story as a boy and pursued his dream of one day finding the ship.

“It’s a great lesson for kids,” he said. “You can go out and discover history.”

IF YOU GO: More about hours, cost of the exhibit

Christina Barron