Welcome to obscure Washington, D.C. Locals reveal the D.C. you don't know Washington, D.C. holds a lot of nearly hidden history A tennis court occupies the site of the execution of Lincoln assassination conspirators A present-day parking garage once hosted a historic Beatles show Washington (CNN) -- Ordinarily, I'm not a fan of vandalism. But years ago I spotted some graffiti in Washington that struck a chord. Someone had spray painted the symbol for anarchy -- a circled "A" -- on a Chinatown grocery store. And I wondered: Did they know? Did they know that that building, a century earlier, had been Mary Surratt's boarding house? Did they know that conspirators had gathered there to plot the kidnapping and assassination of an American president? Did they know that the site had played a role in the biggest act of anarchy in this country's history? Was the graffiti just accidentally appropriate? Or could punks with paint be profound? I don't know the answer, of course. But I know that this city is teeming with people who, like me, relish its hidden history. Washington is a town of majestic monuments and memorials. And those are worth visiting. But if you limit your sightseeing to the obvious -- if you ignore the obscure -- you'll miss the good stuff. That is what I had in mind when I asked historians and history buffs to show me places -- off the beaten path -- that have stirred their love of history and this great town. Four boys, in dire need of haircuts, come to town, looking to conquer it. The British tried it once before, in 1814. Burned the city. It left a bad taste in everyone's mouth. But this time, they try soft diplomacy. A little twist and shout. A little ditty about wanting to hold your hand. And it works. Improbable as it sounds, it happened in a barrel-shaped architectural ruin just north of the Capitol on 3rd Street NE. Shortly after 8:30 p.m. on Feb. 11, 1964 -- two days after appearing on "The Ed Sullivan Show" -- the Beatles took the stage in Washington Coliseum. It was the Beatles' very first stage concert in the United States. Critics later say the concert is as singular moment in rock history -- a moment when the early Beatles seemed even more joyous than their shrieking teen-age fans. Richard Layman, who fought to preserve the Coliseum, cherishes this place for many reasons. Built in 1940 and 1941, the building served as an ice rink, sports arena, worship hall, trash transfer station and parking garage. Nation of Islam leaders Malcolm X and Elijah Muhammed spoke here. It hosted numerous professional sports teams, and was home to the Ice Capades. For Beatle devotees, this is a shrine. They still have ticket stubs, and remember whether they paid $2, $3 or $4. They gush about how Paul smiled at them. An age of innocence? The Russians threatened us from outer space. The pains of segregation and integration were rocking the country. And, just three months earlier, an assassin felled the leader of the free world. But for about 35 minutes on a cold February night in 1964, four boys from Liverpool entered a converted ice rink and warmed a generation's heart. COURTROOM DRAMA: Last act of the Civil War The man, a tavern owner, took the witness stand. "I was acquainted with John Wilkes Booth," he said. Booth came into my restaurant [adjoining Ford's Theater] on the evening of the 14th of April. Booth "walked up to the bar, and called for some whiskey, which I gave him; he called for some water, which I also gave him; he placed the money on the counter and went out. I saw him go out of the bar alone, as near as I can judge, from eight to ten minutes before I heard the cry that the President was assassinated. Peter Taltavul spoke those words, in this room, just one month after Lincoln died. By then, authorities had already tracked down Booth, cornered him, and killed him. And they had rounded up eight people who they believe had assisted him. They convened a military commission to conduct the trial in the third floor of what was then a federal penitentiary. The co-conspirators, they reasoned, were not "civilians," but were "enemy belligerents." The nation was seeking justice and vengeance, and it would come swiftly. On July 6, 1865 -- less than three months after the assassination -- the commission found all eight conspirators guilty. It sentenced four to hang, and four to prison terms. The condemned were hanged the next day. A year later, the Supreme Court would rule that a defendant could not be tried by military commission when civilian courts were functioning. But it was too late. The penitentiary is now closed and largely demolished. The land is part of Fort McNair at the southernmost point of Washington. Visitors -- mostly lawyers and Civil War buffs -- are frequently overwhelmed when they enter the room, said Susan Lemke, a special collections librarian who has accumulated artifacts related to the trial. "There's no substitution for actually witnessing or being in the middle of a historic site like that," she said. THE GALLOWS: Where generals "serve," conspirators hanged Michael Kauffman is struck by the incongruity of it all. On the edge of a Fort McNair tennis court, where generals now casually toss their gym bags, Abraham Lincoln's death was avenged. Here in this spot, near the penitentiary room where the sentences were handed down, on a miserably hot day in July 1865, Union Army Capt. Christian Rath raised his hands and clapped three times. On the third clap, soldiers knocked supports out from under a gallows, and four prisoners fell. Their bodies jerked violently at the ends of their ropes. The prisoner in the dress appeared to die instantly. But one of her three accused accomplices writhed for five minutes before surrendering his ghost. "I am one of those people who think that if you really want to understand history, you have to go to where it happened," says Kauffman, an expert on the Lincoln assassination. So Kauffman leads me to this empty tennis court. It is drizzly and cold, and there is little here to evince the images and emotions of that hot July day. The penitentiary's tall wall has been demolished, and a building prominent in photos of the hanging has been altered almost beyond recognition. Almost. Kauffman shows me the place where the wall met the building. And in my mind's eye, the gallows fall into place. There's this strange sort of excitement that you get when you've read about something, and you visualize it, and you think you know all about it. And then all of a sudden you go there and it's right in front of you. It surrounds you. And it's always somehow different from what you had imagined," Kauffman said. Different, to be sure. But more real than ever. CHADWICKS: Where the U.S. was shaken, and stirred It is known as "The Big Dump." On June 16, 1985, CIA officer Aldrich Ames walked into Chadwicks, a Georgetown pub, with two shopping bags full of classified information and, over lunch, gave them to a Soviet diplomat. "In those bags was every piece of paper he could get his hands on that revealed almost all of our operations in the Soviet Union," said Peter Earnest, a former CIA official who is now executive director of the International Spy Museum in D.C. Five to seven pounds of secrets. The enormity of the breach became known only after the Soviet Union began rounding up some of the United States' most valuable assets in Russia. At least 10 were executed. The CIA launched a hunt for a possible mole. It compiled a list of 190 CIA officers with access to relevant classified information, and culled it to 28. And in 1994 -- nine years after the Big Dump -- Ames and his wife were arrested. Earnest says he doesn't "romanticize" the Chadwick's site, but says "the repercussions of what he did ripple through the government today -- the need to have more polygraphs, the concerns about our records ... the nature of the questions asked." It's also a waypoint in the Spy Museum's bus tour, which notes the role that Ames' "high-maintenance" wife Rosario played in his betrayal of his country. Tour guides note that after Ames was arrested, FBI agents who eavesdropped on their conversations made an astonishing comment: They were so disgusted with Rosario's constant badgering about money, her criticisms of Ames and her treatment of their son that although they could never forgive Ames for spying, they said, they would have understood if he had killed his wife. The sign is long gone, but the building, known as the "Alexandria Slave Pen," still stands in Alexandria, Virginia, just across the river from Washington. I often tell my students, 'You've gone into towns where you just see row after row of car dealerships. Duke Street was that -- but slave dealerships,'" says Chandra Manning, associate professor of history at Georgetown University. In 1861, the slave trade was thriving when Virginia seceded from the union. But on May 24 of that year, the Union Army's First Michigan Infantry marched into town, and one of the first things it did was liberate the slaves. Ironically, the slave pen became a refuge for runaway and freed slaves seeking the protection of the Union Army. Today, 1315 Duke Street is home to the Alexandria branch of the National Urban League, a civil rights organization. A historical marker stands outside, and there's a small museum in the basement. But Manning believes most passersby have no idea about the building's horrific past. Most, but not all. "If you're walking with me," Manning says, "you have no choice but to know what happened here." THE FORGOTTEN CRASH: History lost and relived On a fog-shrouded evening on the penultimate day of 1906, a dead-heading train roared down this stretch of tracks near Washington's Catholic University, coming upon a slower passenger train heading the same direction on the same track. There was no time to stop. Railroad workers have an antiseptic -- but descriptive -- word for what happened next: Telescoping. The massive steel engine of the speeding train plowed through the flimsy wooden passenger car of the slower train, killing and dismembering its occupants. It plowed through the next car as well, and the one after that. When the trains came to a stop, cinders and soot from the locomotive's fire box rained down on the splintered wooden planks, clothing, Christmas gifts and human remains. Fifty-three people died, and more than 70 were injured. Today, the "Terra Cotta" crash is all but lost to history. Every day, thousands pass the site, where there isn't even a hint of the horror that happened. But Richard Schaffer, a D.C. firefighter who spent 10 years researching the crash, says Terra Cotta nonetheless changed railroading. It hastened the conversion of passenger cars from wood to steel and led to improvements in railroad signaling. That happened, he says, because the crash happened on "the route to Congress." There's a saying, sometimes attributed to Mark Twain: "History doesn't repeat itself, but it does rhyme." History rhymed in June 2009 -- nearly 103 years later -- when a D.C. Metro subway train plowed into another subway train. The cars telescoped, killing nine and injuring dozens. "The irony was it was practically the same location and practically all the same problems, human error, signaling problems, construction quality of the trains," Schaffer said. Both wrecks deserve to be remembered. "If you forget what's happened before you," Schaffer says, "you don't have a foundation to live upon." Can there be any doubt what happens here when the sun goes down? Can there be any doubt that, when the gates close and the last visitor leaves this historic burial ground, band leader John Philip Sousa reaches for his baton, Civil War photographer Mathew Brady tweaks his camera, and J. Edgar Hoover tries to keep the whole mess under control? This is Congressional Cemetery, where Washington's political and social establishment rests in eternal peace. In the 1800s, its heyday, this was the site of grand funeral processions. Tens of thousands of Washingtonians would gather to watch soldiers carry fallen leaders down a slate path to graves or crypts. "I'm sure there are quite a few secrets buried here," says Abby Johnson. Abby and her husband Ronald, professors of literature and history respectively at Georgetown University, take me to the "Public Vault," a crypt the size of a one-car garage. Built in the 1830s, the vault was used to store the bodies of public officials until the ground thawed, or until they were moved to other locations. You need a skeleton key, of course, to get inside. Dolley Madison slept here. As did three presidents: William Henry Harrison (1841), John Quincy Adams (1848), and Zachary Taylor (1850). Harrison's three-month stay was three times longer than his presidential term. All the presidents' bodies have since been moved to their home states. Today, Congressional Cemetery, which boasts of being "in the shadow" of the U.S. Capitol, is overshadowed by a more prominent cemetery -- Arlington. But the Johnsons are devoted to keeping Congressional's memory alive. At least as long as they are alive. And then maybe, just maybe, beyond.