America's little-known castles, displaying 'raw power,' are hiding in plain sight

When most Americans think of castles, they likely picture medieval fortresses towering over European hills. 

Yet the history of these imposing structures is much closer to home than many might realize.

Speaking to Fox News Digital from England, historian Dan Jones described his latest book as a 3,000-year journey through human history, from the Sack of Troy to the Nuclear Age, as it explores the broader history of castles and fortifications.

From Iron Age hillforts to classic medieval castles and beyond, "Castles: A Fortified History of the World," explores fortifications across different eras and regions of the world, including Japan's Himeji Castle and nuclear bunkers built during the Cold War.

Jones examines the role America has played in the broader history of castles, from early fortifications to Civil War-era forts.

"I don't think we can truly understand it without having the American side to the story," said Jones.

One notable example is Fort Sumter in South Carolina, where Confederate forces opened fire on Union troops in April 1861, marking the beginning of .

'HIGHLY UNUSUAL' CANNONBALL CACHE FOUND AT CONSTRUCTION SITE IN COASTAL CITY MAY BE WORLD'S FIRST

Jones described Fort Sumter, a coastal fortress built with thick brick walls and artillery defenses, as one of the "descendants of castles" that emerged in America.

Another important moment in the history of castle building, Jones said, came when Union forces attacked Fort Pulaski in Georgia with rifled cannons in 1862.

The fort had been considered nearly impenetrable, but was "blown to bits" within 48 hours, Jones told Fox News Digital.

"Fort Pulaski was just thought to be so strong, you may as well bombard the Rocky Mountains," Jones said.

RARE CANNONBALL EMERGES FROM GROUND AT THE ALAMO, LIKELY UNTOUCHED FOR NEARLY 190 YEARS

"Well, Fort Pulaski was blown to bits in 48 hours, and that was a transformative moment in the whole history of castle building."

Beyond military forts, America is also home to grand, castle-like estates built as displays of , including Hearst Castle in California and Gilded Age mansions such as the Biltmore Estate in North Carolina and Belcourt in Newport, Rhode Island.

Asked about the historical significance of America's grand, castle-like estates, Jones said that castles have long served two purposes: providing defense and displaying wealth and power.

In that respect, many of the grand estates built during followed the same tradition as the magnificent residences of medieval kings and nobles.

"There's this moment in the Middle Ages where they're combined, but you can see this in America today," Jones said.

"There are colossal fortifications and there are these colossal palatial houses that have always been built by the super wealthy."

He pointed to , built in 1955, as another example of the enduring appeal of castles in the popular imagination.

"These are as much a part of the story of castles as the sort of classic medieval ... stronghold," he said.

Even so, the romantic image of castles often contrasts with their darker history.

"The castle can sit on the landscape to intimidate, to terrify, to be a display of raw power," he said.

The history of castles is, of course, also filled with gruesome detail