It fell out of use sometime in the Taft administration and was razed to its foundation in 1912.

After nearly a half-century of housing the horses that carried presidents, the Executive Stable -- what was left of it -- spent 90 years as part of Washington's paved-over past, joining centuries of foundation stones, bone fragments and other artifacts of everyday life beneath the ground.

That is, until three years ago, when plans to improve security around the White House put the area in the hands of archaeologists charged with the task of uncovering the stable.

"It's something you hadn't thought of," said John Bedell, a senior archaeologist with the Louis Berger Group Inc., which excavated the site under contract with the National Park Service. "Of course the president had a carriage and had horses. But where were they?"

They stood, Bedell and his team of four archaeologists learned, near the intersection of 17th and E NW.

Digging by hand and with machines, the team navigated the remnants of nearly a century of below-ground projects -- a 19th-century sewer line, a working sewer, telephone and electrical lines -- as they unearthed the foundation walls of the stable and a large iron fence that had stood in front of it.

"It's a bit of forgotten history," Bedell said.

The White House stable is part of an underground legacy that stretches throughout the city. Beneath what is now the Ronald Reagan Building, at 1300 Pennsylvania Ave. NW, archaeologists found traces of a once-raging red-light district. And buried below what is now Barney Circle were relics of a prehistoric Indian village.

In a city where monuments mark almost every major passage of our nation's history, countless fragments of the past remain forgotten, either lying beneath the ground or tucked away in obscure offices.

"There's a very rich history of the city, and that history, both that which is written and that which is unwritten, is left to be discovered through archaeology," said Stephen Potter, archaeologist for the National Park Service's national capital region.

Like some other significant finds, the Executive Stable was uncovered as part of a modern construction project.

The excavation occurred as part of aesthetic improvements to White House security, replacing a fence that had been erected after the Oklahoma City bombing with more attractive security bollards. The archaeologists first uncovered the foundation of an iron fence around the stable; it was so large they initially thought it was the stable. They also found horseshoes and bottles, probably left by people who had worked at the stable. The artifacts are now "working their way through the Park Service bureaucracy," Bedell said.

When they emerge, they will become part of the large collection of artifacts of the District, unearthed from a few inches below the city surface and dispersed in paper bags and cartons in archives of government agencies and curatorial facilities.

The artifacts include such objects as old medicine bottles that dispensed cocaine to 19th-century city dwellers and prehistoric pottery fragments. But they are not always easily accessible. Many artifacts are kept in the D.C. Archives, while others are on display at the City Museum, said Nancy Kassner, the archaeologist with the District's Historic Preservation Office. Kassner keeps some in the Historic Preservation Office, including six cartons that she calls Howard Road, which contain items unearthed during an excavation beneath the present-day Anacostia Metro station and now sit beneath a cubicle desk. Another 10 boxes or so are in Kassner's basement.

Soon, Kassner hopes, that will change. She is working with the City Museum to build an archaeology lab, where the museum can showcase Washington artifacts and incorporate archaeology into educational programs as a hands-on way to teach history and science

Kassner hopes to consolidate the artifacts so researchers and the public can easily view and use them.

Beyond that, archaeologists hope the archaeology lab will help Washingtonians learn about the prehistoric life of the city and offer a counterpoint to the image of archaeologists as Indiana Jones figures exploring remote deserts in exotic lands.

Washingtonians have been unearthing artifacts for years, since at least the days of William Henry Holmes, a 19th-century curator of the U.S. National Museum -- now the Museum of Natural History -- whose explorations along the Potomac River earned him a reputation as the father of archaeology in Washington.

But many artifacts have been uncovered in the last few decades, particularly since the 1966 National Historic Preservation Act, which requires all federally funded projects to account for any resources they would affect. This can lead contractors to hire archaeologists, who use public records, historical maps and educated guesswork to determine what might exist beneath a site and whether a dig might retrieve it.

"The interesting thing about an urban environment is that you never know" what you will find, Kassner said. "Years ago, the thinking was, 'Urban area? No, you're not going to find anything.' "

But searchers have done just that -- on projects including National Park Service excavations of Rock Creek Park and middle school digs of the Sidwell Friends School's back yard.

Like Washington itself, the District's archaeological projects can be separated into the famous and the little known.

Some, such as an excavation beneath Federal Triangle that uncovered portions of the Civil War-era "Hooker's District," unearth artifacts of the everyday lives of non-famous people, supplementing historians' knowledge of the city from over a century ago. Named for the Civil War General Joseph Hooker, the district was home to hundreds of "bawdy houses" in the 1860s before they were replaced with more formally run brothels by the 1890s.

Another project, completed before the MCI Center was built, turned up household trash, wells and building foundations of a heavily populated 19th-century residential area. Researchers used those discoveries to investigate historic water supply and health and sanitation conditions.

Archaeologists excavating the site where the new Convention Center was built found items from the homes of Smith Harley and George Garrison, two free black men whose families lived on Eighth Street NW in the decades before the Civil War. The items from Harley's and Garrison's houses were roughly equivalent to those from houses of their white neighbors, and they remain among the only excavated items from the homes of free blacks before the war.

Other projects, such as the Executive Stable excavation, fit a different purpose: exploring sites associated with famous figures.

"It's not so much knowledge-driven; it's not so much done because you have questions about the past that you want to answer," Bedell said. "It's done because people are interested in these buildings or buildings associated with these people."

Even so, the Executive Stable project did offer a glimpse into people and jobs usually ignored by history. Though historians knew the stables existed -- photographs of it survive -- references to the stables, or to the logistics behind the presidential carriage fleet, are rare in written accounts.

Besides the stable foundation, Bedell's team uncovered foundations from temporary office buildings that were erected on the Mall during World War II, another part of the government's day-to-day life that has been almost lost to history, he said.

"When we go down to the Mall and we look at this lovely park area, the monuments, it hasn't always been this way," Bedell said. "There's a lot of work in Washington to try to keep the government going, and they try to keep it hidden."

Sites like the stable are often buried under layers of fill because the ground in the city is higher than it once was, Bedell said. The area at 17th and E is about five feet higher than it was in 1871, Bedell said, because displaced soil from underground construction projects and years of landscaping have raised the ground level.

The collection of artifacts at the Historic Preservation Office includes many items Kassner has rescued after other people left them at digs. Anything to keep them from "disappearing," she said.

She retrieved a plank of wood from a site near the Washington Navy Yard that was recently excavated in anticipation of the construction of a Department of Transportation building.

There, archaeologists found portions of the wooden walls of the Washington Canal, as well as evidence that it had been repaired during its lifespan. That evidence confirmed that the city had not heeded the advice of Benjamin Latrobe, an architect of the Capitol, who in the early 19th century urged officials to use the highest-quality materials to build the canal so they could avoid repairs.

Nearby, another team recently found evidence of a predecessor to the current Eastern Market, which in about 1804 existed closer to the water, two blocks north of the Navy Yard.

Using soil analysis, archaeologists determined what had been sold in particular stalls, identifying some occupants as meat vendors and some as fish vendors. The team uncovered one side of the U-shaped market and stones and bricks from another portion, and suggested it might have been an open market with arched doorways, Kassner said.

Other finds predate the city's recorded history.

Along the Rock Creek Parkway, at a site called Ramp 3, archaeologists found cremated remains and evidence of a ritual burial, with items radiocarbon-dated to between 640 and 790 A.D. A 16-inch antler comb and shark teeth were found near the body.

An excavation below Barney Circle uncovered stone tools, deer blood and corn fibers, evidence of a prehistoric Indian village.

National Park Service archaeologists are in the early stages of a study in Rock Creek Park that has the potential to "completely turn around what prehistorians thought we knew about Washington circa 700 A.D.," said Potter, the Park Service archaeologist.

Potter said he is often surprised by how little Washingtonians know about the history of their city, particularly when it comes to its prehistoric past.

"It's as though they still believe the history of Washington began with the L'Enfant plan," he said.

Kassner said she hopes the archaeology lab at the City Museum will help make the city's history more widely known and will allow students to become acquainted with archaeology as a hands-on way to explore, and as a scientific process that must be cultivated carefully.

One of the lessons she hopes to impart is that the history of nearly anything may lie just below its surface, a lesson Dave Wood and his fifth-grade science students learned several years ago.

A middle school science teacher at Sidwell Friends School, Wood had scheduled a class trip to an archaeological dig in Virginia. When the trip was rained out, he enlisted the help of local archaeologists, who helped him lead class digs outside Sidwell's administration building, Zartman House. The house, built in 1816, became a magnet for his students' enthusiasm.

"You get these really squirrelly kids, and you couldn't get them out of there," Wood said. "They were having so much fun finding stuff."

John Bedell will discuss the Executive Stable excavation at 6:30 p.m. next Tuesday at the City Museum, 801 K St. NW. For reservations, which are required, call 202-383-1809 or e-mail reservations@citymuseum-dc.org.

City archaeologist Nancy Kassner shows artifacts, taken from the MCI Center construction site, at the City Museum. "Years ago, the thinking was, 'Urban area? No, you're not going to find anything.' "Some of these projectile points, found in Northeast Washington, date back to 3000 B.C., Kassner says.