Gloucester, Mass. ? This busy fishing town at the center of scenic Cape Ann calls itself America’s oldest seaport. Settled in 1623, Gloucester is known for fresh seafood and as a launching point for whale-watch excursions. But it’s also home to two unusual homes, each dating back less than a century, that may prove a worthwhile sidetrip for leaf-peepers and others visiting the area, just a 45-minute drive from Boston.

One of these attractions, Beauport, is a mansion in which each of the 40 rooms was decorated with a different theme. The other, Hammond Castle, is a medieval-style castle complete with drawbridge and lookout tower, built by an eccentric inventor who wanted a fitting home for his 8-story pipe organ.

Small summer retreat

The man who built Beauport on Gloucester’s exclusive Eastern Point, Henry Davis Sleeper, intended for it to be a small summer retreat. But the cottage couldn’t contain his passion for collecting Colonial-era objects. He designed new rooms to accommodate them over 27 years, and earned a reputation as a top interior designer.

“Every room has a theme, whether it’s color, a literary figure or historic period,” said Jessie Olson, site manager at Beauport, also called the Sleeper-McCann House.

Sleeper’s playful style sometimes trumped intellectual concerns or historical integrity. Books throughout the home, for example, were selected for their colors, rather than their content.

“Beauport is certainly the most distinguished home, house, location in the whole area,” said author and historian Joseph E. Garland. “Many recognize Sleeper as being the progenitor of Americana. It’s very idiosyncratic. It’s beautiful. It’s haunting.”

Salvaged paneling

Sleeper salvaged paneling from old New England farm houses and used it at Beauport. He used wood from his mother’s childhood home in Pembroke to build the Pine Kitchen, also called the Pembroke room.

Hammond Castle Museum, the mansion overlooking Gloucester Harbor built by inventor John Hammond Jr. is seen in Gloucester, Mass. Hammond, a protege of Alexander Graham Bell, was inspired by castles during his childhood in England.

Sleeper’s affinity for Revolutionary figures is apparent in the Cathedral room, where the wallpaper is a replica of Paul Revere’s wallpaper at his North End home. The Octagon room is Sleeper’s homage to the French, built when he returned from France after serving in the all-volunteer American Field Service during World War I.

Among the best views of Gloucester Harbor are those from the Red Indian room, which includes a sun room that stretches over the rocks of the shore below.

Odd shapes

Dedham resident Eddie Coggeshall said she liked the odd shapes.

“The roof lines are very unique,” she said on a visit with other volunteers from the Museum of Fine Arts. “The windows were so imaginative. It’s really fabulous. It’s a real secret.”

The youngest son of a Civil War hero, Sleeper was frail from birth and never married. He died of leukemia in 1934 at age 56.

Woolworth heiress Helena McCann and her husband bought the property in 1935, and changed just one room. The McCann family in 1942 gave the property to an organization now known as Historic New England. The nonprofit group offers special events at the house, such as “tea by the sea.” The home was named a National Historic Landmark last year.

‘Father of remote control’

The view from Beauport also includes a look across the harbor at Gloucestor’s other unusual attraction, Hammond Castle, which is named for the man who built it, John Hays Hammond Jr. Hammond’s work was ahead of its time, but he preferred to live in the past.

Known as the “father of remote control,” Hammond built the castle between 1926 and 1929 in the Magnolia section of Gloucester.

“There’s nothing like it,” said Garland. “It’s very dramatic, very medieval. It’s a genuine curiosity. It was built as a genius’ home and laboratory..”

Hammond had an easy commute to work — Hammond Radio Research was housed in the castle. From those labs, he produced more than 400 U.S. patents, second only to Thomas Edison.

Military officials first took notice when Hammond in 1914 developed remote control through radio waves.

Visitors to the Beauport, also known as the Sleeper-McCann House, Eddie Cogeshall of Dedham, Mass., left, and Sharon McKay, of Carlisle, Mass., tour the exterior grounds in Gloucester, Mass.

That’s when Gloucester’s better-known industry — fishing — came in handy.

“He had this lobster boat going around the harbor with no one on board,” said Garland. “He was able to control the wheel of a boat using radio signals.”

A love of castles

The son of a mining engineer, Hammond’s early years were spent in South Africa. Just before the turn of the century, his family moved to England, where 10-year-old Hammond fell in love with castles.

Hammond built the castle for his wife, Irene, and to house his collection of Roman, Renaissance and medieval art and artifacts. It cost him $500,000, according to a 1932 newspaper story displayed in the castle.

The newspaper noted that “sticklers for the purity of architectural style may gaze aghast at its conglomeration of styles and periods.”

Hammond, asked why he built the castle, told the reporter: “I am interested in pipe organs. I needed more room.”

The 8,200-pipe organ stands at the head of the Great Hall, where Hammond and his wife threw lavish high-society parties. The Great Hall has various religious themes, including a “Bishop’s chair.”

Hammond, in fact, bequeathed the castle to the Archdiocese of Boston upon his death in 1965. The church sold the property to the nonprofit Museum Trust, which manages it today.