Start at 4000 Nebraska Avenue NW, the private residence of the ambassador of Japan since 1977. Behind the taupe fence surrounding this 12-acre estate is a flat-roofed concrete and stone home with picture windows. It overlooks a traditional Japanese garden and a teahouse that seems to float on a pond.

       Next door at 3900 is the ambassador of Sweden’s 1923 Spanish-style home. The Nordic diplomat and his Asian neighbor both have tennis courts.

       Across the street at 4001 Nebraska Avenue NW are the NBC television studios. The public can’t visit, but it’s cool to see where Meet the Press is taped. It’s the longest-running TV show in history. NBC is also where the Muppets’ Kermit the Frog debuted and where the second of the four Nixon-Kennedy debates was held. They were the nation’s first televised presidential debates.

       NBC’s next-door neighbor at 3801 is the U.S. Department of Homeland Security. DHS was created from 22 diverse federal departments and agencies in 2002. It chose a very historic home: the Mount Vernon Seminary, the first school of higher education open to women in D.C. The school moved there in 1917. In 1942, the U.S. Navy took over its Georgian Revival dorms and classrooms, so the school moved to Foxhall Road NW. By the end of World War II, more than 5,000 civilians and soldiers worked at the Navy’s communications security section (OP-20-G) breaking Japanese and German codes, according to the National Security Agency (NSA).

       Across Massachusetts Avenue NW is American University, which was chartered by Congress in 1893. Alice Paul is a three-time graduate of American University and the Washington College of Law, the school says. Paul wrote the original Equal Rights Amendment, founded the National Women’s Party, and played a key role in securing women’s right to vote. These days the school is home to WAMU, American University Radio, a member of National Public Radio.

       At the end of American University, turn left onto Foxhall Road NW. Walk past tall oak trees and vintage brick, Tudor, and fieldstone homes for six blocks. On both sides of the road at Edmunds Street NW are entrances descending to the Wesley Heights Trail. Managed by Rock Creek Park, this ivy-covered stream-valley trail links Battery Kemble and Glover Archbold parks.

       A bit farther down this shady, two-lane road on the right is the walled residence of Spain’s ambassador. This contemporary-style brick building was built in 2003 by Pritzker prize–winning architect José Rafael Moneo.

       Across the street is the Kreeger Museum. David and Carmen Kreeger jointly amassed their modern and African art collection, which includes works by Monet, Picasso, and Van Gogh, the museum says. “I never bought art as an investment,” said David, GEICO’s former chairman. “I bought it for love, and I was lucky.” Washington is lucky that the Kreegers chose Philip Johnson to design their modern, travertine home. When he was awarded the Pritzker Architecture Prize, the group called him “one of architecture’s most potent forces.” He designed the home in 1963, and it became a museum in 1994.

        Downhill on the right is the wooded estate of Belgium’s