Behind all the gray shingles and white trim, many homes on the island boast spectacular interior design and architecture that are redefining the Nantucket aesthetic. Yet for some homes, it is not what’s inside their walls that truly sets them apart—but rather what’s underneath them. We climbed down into some of the island’s most extravagant subterranean spaces to see what’s really happening below the surface.

"When we do home theaters our goal is to create an environment where the outside world goes away,” said Mike Alpert, the president of Nantucket Media Systems. “We get rid of all the distractions and have the sound and video be just right so that you get pulled into this alternate reality.” Few of Alpert’s projects have achieved this better than this home theater located in Tom Nevers, which Alpert designed alongside architect Chip Webster. The room is entirely sound isolated, meaning that no noise from the outside can be heard. Meanwhile on the inside, the walls have been expertly sound treated to ensure the best audio quality accompanying the films playing on the 150-inch screen. Along with a top-of-the-line projector, the theater is equipped with sophisticated automation technology that adjusts the screen to fit each film’s format and dims the lights when the movie is beginning. When the credits begin to roll at the movie’s conclusion, the lights come up and the music softens just like in a commercial theater. Enhancing the unique design of the room, onyx wood backlit by LED lights makes up a bar as well as columns running down the walls. The year this home theater opened, CE Pro magazine named it the best of its kind in the country. Indeed, this home theater truly is a blockbuster.

When Joe Kennedy purchased his island home on Surfside from Mark Lombardi, the property’s former owner had some parting words that Kennedy always remembered. “I designed this place to live out my dreams,” Lombardi told him. “I am blessed to have achieved them.” While the sprawling estate dazzles guests with its elaborate formal gardens and function barn, the main residence’s “coup de grâce,” as Kennedy refers to it, is hidden beneath the ground. Down a hall lined with movie posters (as seen in this story’s opening photo), which accents a state-of-the-art home theater, and down a massive stone stair entryway, there is a wine cellar that appears plucked straight from Tuscany. With a custom-painted domed ceiling and reclaimed brick walls, the rustic tasting room hearkens to Old World Europe. When entertaining, Kennedy enjoys starting the evening in this wine cellar where guests can pull a bottle from one of the hundreds lining the walls and be transported to another world entirely.