Most people drive by commonplace structures and notice nothing. But Martin Mooney sees peculiarities of development, form, and function, grabs his Nikon from the seat of his Red Top cab, coddles the lens, and clicks.

He first noted the large rosy-doored, ivy-covered “vault” on Rock Creek Parkway near the Massachusetts Avenue overpass a few years ago. It’s purpose—past or present—intrigued him.

Two weeks ago, Mooney, his son Zoom—an aspiring radio talk show personality known as “Rick” on-air—and I set off in Mooney’s impeccably clean and mercifully air-conditioned cab to take a closer look at the structure. The two men, speaking in the polite parry of a parent and child who have recently discovered each is an adult, explain that Mooney had been taking Zoom, and his daughter Noelle, on similar photographic expeditions since they were little and lived in Fairfax. As neighboring pastures and woodlands were leveled to make way for tract mansions, Mooney became obsessed with “old things that are disappearing and new things about to be built.” Until about five years ago, Mooney worked as a government photographer and free-lanced for the Washington Star and UPI on the side. But as the Star and UPI shuttered, Mooney felt his creative outlets vanish. “I did 10,000 grip-and-grins,” he says of his job, “and nothing was as carefully documented as the new air conditioning system in the Government Printing Office. There was no creativity. I hated it.” One day he just left work and never went back. He drifted into hacking, which exposes him every day to new subjects to shoot—airport expansion, highway construction, and strange outposts on Rock Creek Park.

He pulls the cab onto the grass across the parkway from the vault, and we dart through traffic to the median strip and then again to the other side. One close look at the giant metal door confirms that it has not been opened in years. Soil is packed against the door’s base; tendrils of ivy have rooted along the hinges. The back of the structure is built into the hill below tony Kalorama Heights. Mooney points out stone steps—obscured from the sight of passing motorists—that lead up the right side of the structure. At the top is a small door. In a tiny, silver box by the door is an old-fashioned security watch key. Feeling a bit like Alice, I grab the handle, twist and push.

To our complete surprise, the door opens. We enter and flick on the lights.

A 15-foot cube, the room is dry, with brick walls and concrete floor and ceiling. Electrical boxes are mounted on the left wall, a small pile of lumber scraps lies in one corner. The room is stacked—like an upper stair—on the much larger chamber below, which lies behind the giant red door. A gloomy and seemingly bottomless staircase leads down to the giant room, but that light switch doesn’t work, and after a few tentative steps it seems foolhardy to descend further into pitch darkness. We content ourselves with peering through a window from the top room to the vault below. A bit of light streaming in around the hinges of the giant door vaguely illuminates giant beams or hoists dedicated to an unknown purpose.

After a few minutes of echoing speculation off the walls, we leave. On the way back, I look at an album of Mooney’s work. Prints of foundations being laid, cranes in action, a final shot of a restaurant due for demolition—photos that Mooney will cede to area libraries and historical societies. It’s a monument to the seemingly mundane transformations of the metro area. But as Auggie Wren tells Paul Benjamin in Wayne Wang’s Smoke, if photos of incremental change, of everyday life and its landmarks all look the same, then you aren’t really looking.

A Washington City Paper T-shirt will be awarded to the person who writes the best humorous or factual explanation of Rock Creek’s vault. Inspired answers will appear in next week’s edition if they reach us by Tuesday. Submit your description, or suggest topics for this column, by writing to: Mysteries, Washington City Paper, 2390 Champlain St. NW, Washington, DC 20009. Our fax number is (202) 462-8323, or e-mail us at No phone calls, please.