Nikola Tesla Mentored the Inventor Who Built This European Castle in Gloucester, MA

The Hammond Castle, Massachusetts

In 1929, one of America’s most prolific inventors decided to build himself a castle in Gloucester.

Hammond filled it with European artifacts, hidden passages, and a massive pipe organ. But also used it as a lab where he developed remote control technology and worked alongside names like Tesla.

Today it’s exactly as weird and wonderful as he left it.

The Inventor: John Hays Hammond Jr.

Born in 1888 to a wealthy mining engineer, Hammond wasn’t your typical rich kid.

He turned out to be one of America’s most prolific inventors, holding around 800 patents and earning the nickname “The Father of Remote Control.”

Working alongside Thomas Edison and Alexander Graham Bell, he developed crucial tech for radio control, guided torpedoes, and the TV remote.

He was both genius and showman – equally comfortable doing groundbreaking work in radio waves and hosting elaborate parties where he’d try to contact spirits through his pipe organ.

Where science meets history and art

Hammond designed the castle himself, mixing architectural styles from ancient Rome through Gothic Europe.

The place is packed with legit ancient artifacts he collected, including a Roman sarcophagus and 15th-century furniture.

But it’s also built for science – he included state-of-the-art labs where he developed his inventions.

Hammond loved diving from upstairs windows

When he felt happy, Hammond would jump from a second-floor window straight into the courtyard pool. This 15-foot drop became his favorite way to surprise guests at parties.

He made sure the pool was deep enough and colored the water just right for these jumps. You can still see the exact window ledge he jumped from on the east side of the second floor.

He worked nights and slept all day

Hammond kept a night owl schedule, working through the dark hours in his lab and sleeping during daylight.

People nicknamed him “The Electronic Sorcerer” because of this unusual habit. You can join Thursday evening Candlelight Tours to see the rooms like Hammond did during his nighttime work.

Many of his best inventions, like improvements to FM radio and single-dial tuning, came from these late-night sessions between 1926 and 1929 while living in the castle.

A Columbus crew member’s skull lives here

One of Hammond’s strangest treasures is a human skull that supposedly came from someone on Columbus’s ship. You can see this creepy artifact displayed in the castle today.

Hammond bought it in the 1920s from a collector in Spain who said it was dug up in the Caribbean.

While nobody has proven it’s really from Columbus’s crew with modern testing, it remains one of the most talked-about items in the castle.

His spirit might be a black cat

Hammond really believed in ghosts and promised he’d come back after death as a black cat. Since he died in 1965, people have spotted mysterious black cats appearing throughout the castle.

He and his wife Irene often held séances in their home. You can join Spiritualism Tours by Candlelight on Thursday evenings from July through October.

Secret passages hide throughout the walls

You’ll find many hidden passages built into the castle’s design. These secret hallways connect Hammond’s lab to other rooms throughout the building.

One hidden path goes from the master bedroom to the Great Hall, letting Hammond sneak away from guests without being noticed.

Another secret staircase links the medieval-style kitchen to the dining room, so servants could bring food without being seen.

The castle’s plans show at least seven secret passages, but not all are open to visitors today.

Four different castle styles combine here

Hammond created his castle by mixing medieval, Gothic, Renaissance French, and Romanesque designs.

The building uses real architectural pieces from the 15th, 16th, and 18th centuries.

You’ll see Gothic cathedral designs in the Great Hall, Renaissance style in the dining room, a Norman tower on the east side, and medieval battlements on the west.

Real medieval storefronts fill the courtyard

Inside the courtyard you’ll find actual medieval storefronts brought over from a 14th-century French village.

These include a bakery, wine shop, and butcher shop fronts with original signs made for customers who couldn’t read.

There’s also an ancient church doorway made from lava from Mount Vesuvius in Italy.

Hammond shipped all these pieces from Europe at huge cost – about $250,000 in 1920s money (over $4 million today).

The storefronts originally stood in market squares in Normandy and southern France.

His antiques might have ghostly visitors

Hammond collected items he thought still had their former owners’ spirits attached. His collection has Roman tombstones, ancient coffins, and medieval religious objects said to be haunted.

Hammond’s wife Irene was big into spiritualism and claimed she could talk to spirits through the antiques.

The SyFy channel’s Ghost Hunters featured the castle in a 2012 episode called “Paranormal Pioneers,” where they found unexplained voices and moving objects.

An 8,400-pipe organ fills the Great Hall

The Great Hall holds a massive pipe organ with 8,400 pipes, once the biggest home organ in the Western Hemisphere. Hammond built it before the castle itself, and famous organist Virgil Fox played it in the 1940s and 1950s.

Hammond invented a recording device that captured performances for playback, similar to today’s digital music systems. Though Hammond couldn’t play it himself, he held 19 patents for pipe organ technology.

The organ is now being fixed after years of sitting broken.

Hammond lived inside his own museum

Unlike most historic homes that become museums after their owners die, Hammond made his castle a museum in 1930, just a year after finishing it. He kept living there until 1965, basically living inside his own museum.

Visitors could tour parts of the castle while Hammond worked in his lab in another section. The Boston Archdiocese bought the castle in 1975 for $68,000, and organist Virgil Fox owned it briefly after that.

Hammond was first buried in a tomb on the property but was moved to the courtyard in 2008.

Visiting Hammond Castle

You’ll find Hammond Castle Museum at 80 Hesperus Avenue in Gloucester, Massachusetts. The museum is open daily from April 5 to January 4, 2025, from 9:00 am to 3:30 pm, with last entry at 2:45 pm.

• Self-guided tours run all season
• Guided tours begin April 29, 2025
• Evening events include Candlelight and Spiritualism Tours Book ahead at hammondcastle.org.
• The museum isn’t wheelchair accessible because of its historic staircases.