The Diplomat's fourth season may open with an assassination attempt outside Windsor Castle, but the Netflix drama never actually films there. Production designer Curt Beech revealed the patchwork of real locations behind the season's most powerful rooms—and several are worth adding to a travel list.

Windsor Castle, as seen on screen, is actually nine separate locations stitched together. The exterior and courtyard belong to Burghley House near Stamford, while Belvoir Castle, Lancaster House, and the British Foreign Office in London stand in for interiors. State-side fill-ins included the Woolworth Estate and Sleepy Hollow Country Club in New York. The panic room where Kate and Hal are locked down? The crypt of an Upper West Side church.

Back at the ambassador's residence, Wrotham Park in Hertfordshire once again plays Winfield House—the real London home of the US ambassador. Some rooms, like the blue room and library, are filmed inside the estate itself; others, including the green room and blue study, are sets built at Steiner Studios in Brooklyn, where most of the interior work happens. The US Embassy set, originally built on a London soundstage for the Nine Elms building, was shipped to New York and rebuilt. One scene was shot near the actual embassy, which Beech describes as beautiful and increasingly familiar from other shows.

Season 4 also moves the action to a newly designed White House set. Beech ditched the old Oval Office in favour of an invented presidential study with three zones, and filmed a swimming scene in the basement of the Woolworth Building—a nod to the real White House pool that was plastered over and turned into the press briefing room. Downing Street got a rebuild too, with the famous stairs shot at New York's Steinway Mansion and the exterior stitched from footage outside the British Foreign Office plus a Brooklyn parking-lot doorway against green screen.

The standout travel inspiration, though, is Lucca, Italy. The production spent six weeks filming at eight locations in and around the Tuscan walled city, where the season's G7 summit unfolds. Villa Viesca (the former summer home of Salvatore and Wrotham—rather, Salvatore and Wanda Ferragamo) and the resort Dimora Ghirlandaio serve as the American delegation's villas, while summit meetings take place in freshly restored stately homes: Villa Reale di Marlia, Villa Medici at Poggio a Caiano, and Villa Medicea La Petraia. Beech says the team initially considered passing Florence off as Lucca but chose to embrace Lucca on its own terms—fresco-covered halls, custom-built desks and all.

For travellers, the appeal is twofold. England's great estates—Burghley, Belvoir, Ingatestone Hall in Essex (used for the prime minister's home)—are regularly open to visitors and make an easy multi-stop itinerary from London. And Lucca offers a less crowded alternative to Florence, with Renaissance villas, frescoed salons and Tuscan countryside within easy reach. Fans of the show can literally walk through its sets.