Carl Mandis, owner of the Market Inn, stands in his restaurant’s dark-paneled bar and gestures to a framed picture of a naked woman.

“There’s old Marilyn Monroe up there,” he says of one of the dozens of nudes that adorn the walls of the lounge area and at one point even covered the ceiling. “You just can’t miss her, huh? … Everybody always said, ‘Go to the nudie bar at the Market Inn.’ That sort of started it all off.”

Nearly a half century after its opening, the diminutive brick restaurant, located at Second and E streets Southwest in an out-of-the-way perch between elevated railroad tracks and the Southwest Freeway, has proved remarkably resilient. It offers generous portions of fresh seafood and steak along with top-flight live piano music in the bar area seven nights a week.

Entering Market Inn’s doors is like walking through a portal to a different era.

There’s the bell in the entryway, which Mandis recalls ringing up to five times a day as a teenager to summon Members to Capitol Hill when the Cloakroom called (three rings for a House quorum call; one for a Senate “yea and nay” vote). The advent of pagers and cell phones silenced that tradition in the 1980s, Mandis says, as he gives the bell a sentimental ring. At the height of the restaurant’s popularity in the 1960s and ’70s, then-Rep. Claude Pepper (D-Fla.), then-Sens. Alan Bible (D-Nev.) and Hubert Humphrey (D-Minn.), and even former Alabama Gov. George Wallace (D), who would arrive with Alabama state troopers in tow, were known to stop by. And then-Speaker Carl Albert (D-Okla.) threw back more than a few at the inn’s long antique-style bar.

“We are the old school,” asserts Liz Whitehill, Mandis’ sister who is a manager at the restaurant.

These days, Mandis says he can’t “keep up” with all the new Members, who no longer frequent the establishment as if it were their personal clubhouse.

Still, there are plenty of reasons to give Market Inn a second look.

For one thing, the restaurant’s soothing hominess offers a distinct reprieve from some of the newer, ber-hip and occasionally antiseptic watering holes that dot the Capitol Hill drinking and dining landscape. Every aspect, from the cheerful, silver-tongued waitresses such as Olga Stopher and Paula Sutphin (who combined have about 60 years of service) to the large (and refreshingly unhealthy) chocolate cake on display in the entryway to the family photos on the walls (both Whitehill and her daughter were married on the premises) harks back to a simpler, less pretentious time in Washington’s history.

Aside from the “nudie bar,” there’s also a front dining room with classic red banquettes, a portion of which has been sectioned off as the “hangar room” (because of images of fighter planes on the walls), and an automobile-themed back room, dubbed the George “Hane’s room” after a friend of Mandis’ father who owned an auto dealership in Southwest D.C.

Dark-paneled walls throughout give the restaurant an air of mystery — it’s the kind of place you’d expect to find an underworld spy, well-connected mobster or publicity-shy movie star sitting at a booth or a corner table.

“People came here to hide,” confirms Whitehill, unprompted. And authors, such as Margaret Truman (daughter of the late president) and Leon Uris, who used Market Inn as a backdrop in his Cold War thriller, “Topaz” (later an Alfred Hitchcock film), were quick to pick up on this. In addition, according to Charles Brandt’s “I Heard You Paint Houses” — the controversial 2004 biography of Teamster official Frank Sheeran in which Sheeran claims he killed Teamster boss Jimmy Hoffa, who mysteriously disappeared in 1975 — the restaurant also was a key place for some questionable money exchanges.

“I believe there were a lot of things that happened in here,” says General Manager Mike Kipp, noting that the restaurant’s parking lot made it easy for people to “zoom back and forth.”

There are plenty of memorable Market Inn moments that are not so notorious. Former Sen. Chuck Robb (D-Va.) romanced his future wife, Lynda Johnson, daughter of President Lyndon Johnson, at the restaurant. The famously gossipy Martha Mitchell, wife of President Richard Nixon’s attorney general, John Mitchell, loved to hang out at Market Inn and dish the dirt. But the “most exciting” incident, in Mandis’ opinion, occurred during one of Nixon’s inaugurations when Frank Sinatra and his entourage were seen holding court at a big, round table in the bar that was usually reserved for the restaurant’s regulars. Sinatra apparently had been denied entrance to an inaugural event and decamped to the Market Inn to lick his wounds.

Later, during the Watergate scandal, the Supreme Court justices huddled around that same table. “One Saturday morning they came in for an early lunch to discuss what to do if Nixon should decide not to step down,” Kipp says. He adds that he had “no idea” what was going on until he got a call from journalist Bob Woodward, who was writing “All the President’s Men” and wanted a copy of the justices’ bill. Kipp declined to do so.

Still popular with House staffers and astronauts (Buzz Aldrin and Tom Stafford have signed the restaurant’s autograph book) who drift in from the nearby Ford and NASA buildings, the Market Inn also has a following among locals such as Stan Cofield, a blind National Park Service worker who often comes for takeout. (On a recent Tuesday, Cofield dozed comfortably in a booth as he waited for crab cakes to take home to his paralyzed wife.) Then there are the loyal Midwestern businessmen and associations who can’t seem to get enough of the place. (Yes, there is an early bird special.) The Indiana Statewide Association of Rural Electric Cooperatives, for instance, has hosted an annual event there for the past 15 years.

Much like the regulars, the list of boldfacers who have made an appearance at Market Inn is surprisingly diverse. Paul Newman, Eddie Murphy and even Geraldo Rivera (who changed clothes in Mandis’ office) have all dropped in. There was even a night in the 1980s when the great Russian ballet dancer Rudolf Nureyev brought in then-National Symphony Orchestra conductor Mstislav Rostropovich for a meal and returned the following evening with friends, Stopher says.

The restaurant business is in the Mandis family blood. Mandis’ paternal grandfather, William, who was a guard for King George I of Greece before he immigrated to the United Streets in the early 1900s, once owned a “little place up in Northwest” D.C. Mandis’ father, John, founded Market Inn in December 1959 in a warehouse that at the time was part of the Southwest market center, which ran from Second to Fourth streets. The center was later torn down to make room for the Independence Square development, which opened in the early 1990s and includes the Office of the Comptroller of the Currency and NASA.

The Market Inn wasn’t the Mandis family’s only venture.

In the late 1960s, Mandis’ father also had a restaurant at RFK Stadium, and several of the sports stars who played there also frequented the Market Inn. (For years, Market Inn ran a bus to Redskins games, and the walls are still covered with old black-and-white team photos.) Another now-defunct Southwest restaurant started by Mandis’ father, the Road House Inn, was sold in the early 1970s.

Since his father’s death in 1971 and his mother Hilda’s passing 11 years later, Mandis, 64, has run the restaurant with the support of a loyal staff that in addition to his sister includes the Richardson brothers — Carl, William and Casey, who have been cooking in or managing the kitchen for more than three decades — and Kipp, a childhood friend of Mandis’ who has worked at the restaurant since its inception.

The menu has remained essentially unchanged. “Ninety percent” of the 1959 menu “is the same as it is today,” Mandis says. “We used to do stuff like turtle steaks that we don’t do anymore. … [But] we still have turtle soup.”

Crab and lobster are the specialities of the house. And crab cakes, crab imperial and stuffed lobster with crab are among the most popular orders, Mandis says. But you can’t go wrong with many of the other vast meat, fish and pasta selections.

Indeed, there are few experiences more satisfying than kicking back with a plate of jumbo coconut shrimp while basking in the orange glow from the lights that line the bar. On weekend nights, the uncle-and-nephew duo of Dewey and Mac Holloway (on piano and bass) play long-ago standards such as “Tangerine,” “I’m Gonna Sit Right Down and Write Myself a Letter” and “What a Difference a Day Makes.” It’s guaranteed to take you to a place far away from the D.C. rat race. The drinks are large, and you can extend the evening by digging into one of the restaurant’s generous slabs of chocolate cake. You may even forget you’re in Washington at all.