Brett Abrams is happy. Abrams is a local historian and author of “Capital Sporting Grounds: A History of Stadium and Ballpark Construction in Washington, DC.” Today he’s leading me on a tour of the city’s sports facilities, built and unbuilt, still standing and long gone.

But for a bit of our time together, I get to play tour guide. I take Abrams, who loves old sports buildings as much as I do, over to 3rd and M Streets N.E., to my favorite structure in town, the Washington Coliseum. He knows about its history. But he didn’t know about its present.

So until today he’s never been inside.

“The greatest thing about this building is: It’s still here!” says Abrams, walking among the rows of parked SUVs with a huge smile (pictured above). “That’s really something.”

Yes it is. The Coliseum, built in the 1940s by local icemaker Migiel “Mike” Uline to host shows from touring entertainment troupes like Ringling Brothers circus and the Ice Capades, had been on death row for decades. Its useful life as a sports arena and major concert hall ended when Abe Pollin opened the Capital Centre in Largo in 1973, and in the years since it has been abandoned, hosted occasional Chuck Brown go-gos, used as a trash dump from 1994 to 2003, and, for the last several years, served as a pay parking lot.

There’s water damage all over the place from the years of inattention, and it’s dark as hell inside. But that’s nothing compared to the fact that you can drive or walk over the very floor where so many big, big things happened.

Rocky Marciano, the only heavyweight boxing champ ever to retire undefeated and stay retired, fought at the Coliseum. Red Aeurbach got his legendary pro basketball career started here, coaching the Washington Capitols of the Basketball Association of America, an NBA precursor, from 1946 to 1949. And, most famously, in February 1964, John, Paul, George and Ringo played their first US. show here on their way to taking over the world. A lot of seats from the arena’s heyday remain in the upper levels and corners.

For a building with such a great resume, there’s not much fanfare about the Coliseum. The most obvious sign that this ground is hallowed comes with a stenciled pair of brown beetles somebody painted outside the parking lot’s entrance a few years ago. Most folks in DC don’t even know the building still stands.

The coliseum is now owned by Doug Jemal, who is not only quite aware of his building’s past, but has also said many times that he keeps that past in mind whenever any plans to develop the property are proposed.

You can’t help but feel the history when you walk in the place.

“There’s the walkways!” Abrams says pointing upstairs. “Still here!”

For some folks, including me and Abrams, that’s, as he said, really something.