Just outside the British Embassy in Washington stands a bronze, nine-foot likeness of Winston Churchill. With one hand on his cane and the other held high in his signature V-for-victory gesture, the prime minister and wartime leader resolutely faces the traffic on Massachusetts Avenue NW. But few of the thousands who pass by each day are aware of what is lodged beneath Sir Winston's feet.

The English-Speaking Union, which sponsored the statue, also inserted a time capsule in the foundation. It was sealed Nov. 28, 1966, and is to be opened on April 9, 2063, 100 years after Churchill was made an honorary U.S. citizen.

Inside the stainless-steel canister are photographs, microfilmed documents and audio and video recordings honoring the life and times of the great man. There also is one of his favorite cigars, still in its original aluminum tube.

A technical note explains, "It is hoped that the correct degree of humidity will be retained for the benefit of anyone in the year 2063 who cares -- or dares -- to savor the aroma that so often inspired Sir Winston Churchill."

Hope for the future, pride in the past -- time capsules reflect many the strong emotions that people feel when they consider the passage of years. These sealed packages of artifacts and messages are buried or otherwise squirreled away at thousands of sites around the world. The Washington area is something of a magnet for them.

With so many landmark structures here and so much national consciousness mixed with the bricks and mortar, we are surrounded by an unseen abundance of tokens for future generations.

They make for a rather eclectic inventory. There is the golden lock of hair in a satin-lined case that President Andrew Jackson placed under the cornerstone of the current Treasury Building about 1836. The lock was from Mary Donelson, infant daughter of the president's adopted son.

"I am placing a part of my heart in this building," Old Hickory said at the time. Donelson later would work for 30 years in the auditor's office of the Treasury, near her lock of baby hair.

Seeds from a magnolia tree planted at the White House during Jackson's administration were included in a 1,000-pound time capsule buried by President George Bush in 1992 to mark the executive mansion's 200th birthday. Other items included paint chips from exterior restoration of the White House and a signed copy of Millie's Book, supposedly written by the presidential pooch.

A time capsule can speak to the purpose of the structure that houses it. The cornerstone of the Supreme Court building, dedicated in 1932, contains, among other things, copies of the Constitution and the Declaration of Independence, a volume of American Bar Association reports and a photograph of the Supreme Court justices of that time.

Into the cornerstone of the first Smithsonian Institution building, dedicated in 1847 and now known as the Castle, went a portrait of James Smithson and documents associated with his bequest to the United States. That gift from the British scientist provided the original funding for the Smithsonian.

Perhaps the most poignantly symbolic of Washington's time capsules are two beneath the basement level of the U.S. Holocaust Memorial Museum. Each is a large metal milk can, containing scrolls of remembrance signed by survivors of the Holocaust.

It was in cans such as these that historian Emanuel Ringelblum buried his chronicle of the Warsaw Ghetto in the hope that the story of the Jewish struggle there eventually would reach beyond the walls.

Nearly 500,000 Jews were confined within the ghetto, and almost all died, including Ringelblum. Remarkably, though, most of his historical record survived. Two of the milk cans were recovered from the ghetto ruins after the war, and one is exhibited in the museum collection.

It usually takes a special occasion to prompt the creation of a time capsule. Often, that event is construction of a new building, but it also can be a civic celebration. One of the biggest was the U.S. Bicentennial.

In 1976, hundreds of capsule-sealing ceremonies were held nationwide but particularly in the nation's capital. Two hundred years after the signing of the Declaration of Independence, it was fitting to see a commemorative time capsule at the National Archives, where the Declaration now resides.

Like most of the Bicentennial time capsules, the free-standing container made of reinforced concrete at the Treasury Building was slated for opening 100 years later at the Tricentennial.

In a statement placed in the capsule, President Gerald R. Ford called it "a meaningful gesture of continuity and communication" with Americans celebrating in 2076. But he added, "There is something about the United States of America that is too mighty to be locked up in a time capsule . . . . No container is large enough to embrace the hopes, the energies and the abilities of our people."

Another landmark event, seemingly made for time capsules, is the arrival of the new millennium, which officially begins on Jan. 1, 2001. This New Year's Eve, however, a national time capsule will be unveiled on the Mall.

Messages from about 400 people who received presidential or congressional awards over the last 10 years are to be included, as well as statements for the future from classrooms in 56 states and territories. The capsulse is to be displayed at the Smithsonian's National Museum of American History before it is eventually sealed.

The year 2000 also marks the bicentennial of the Library of Congress. Celebrations will include the sealing of a time capsule there April 24.

Time capsules can be impromptu, such as one in memory of Jack Kent Cooke at the stadium he built. When Cooke died in 1997, a bricklayer at the construction site took three newspapers reporting the Redskins owner's death and placed them in cinder blocks that became part of a concourse at a 40-yard line.

Time capsules also can be elaborate. George Washington University has its "Vault for the Future," a veritable library of engineering achievement in 1956. Buried beneath a polished granite marker outside the Tompkins Hall of Engineering are 24 copper boxes of reports, photographs and equipment from government agencies and professional organizations.

When engineers of 2056 open the trove, they will find, for example, ball bearings to show production tolerances achieved 100 years earlier. They also will find a device that every self-respecting engineer carried in 1956 but which appears archaic today: a slide rule.

Massive as the vault is, it's not the only time capsule on the GW campus. Another is displayed in the office of the university's president, Stephen Joel Trachtenberg. It's a student's backpack, filled by members of the Class of 1996, the year of the university's 175th anniversary.

It is to remain sealed in its clear plastic case until the 250th anniversary in 2071. The contents have been kept a secret.

Since this city thrives on politics, it's not surprising that even some of Washington's time capsules have been used to help promote causes. In 1988, a 100-year time capsule was buried at Pennsylvania Avenue's Freedom Plaza in memory of the Rev. Martin Luther King Jr. Among other memorabilia, it contains King's Bible and the robe he wore when preaching at Atlanta's Ebenezer Baptist Church.

The Rev. Joseph Lowery, then-president of the Southern Christian Leadership Conference, spoke at the dedication: "Let the record show that . . . we don't intend to wait 100 years for a fuller measure of justice . . . . We've come too far, marched too long, wept too bitterly . . . to let anybody, anywhere, anytime turn back the clock of racial injustice!"

The history of time capsules began long before there was a city called Washington. Placing commemorative items in the foundation of a building is an ancient tradition. With its origins in the stoneworkers guilds of the Middle Ages, the Freemasons fraternal organization has long conducted elaborate dedication ceremonies for cornerstones.

Wearing special garb, including ceremonial aprons, participants perform traditional processions and invocations and anoint the cornerstone with corn, wine and oil, which have symbolic meanings.

Masons do this for their own buildings, such as the George Washington Masonic National Memorial in Alexandria. Laid in 1923, the cornerstone for that 333-foot tower contains articles contributed by Masonic lodges throughout the country. Also, Masons often are invited to dedicate cornerstones of other structures, particularly prominent public buildings.

One cornerstone is generally sufficient for a building, but the U.S. Capitol has at least four. The first was dedicated in 1793 by President George Washington, a Mason himself, as work began on the home of Congress. Subsequent cornerstones in 1818, 1851 and 1959 helped to mark the expansion from the earliest modest structure to the current sprawling edifice.

Little is known about the second Capitol cornerstone, but the other three were given the full Masonic treatment. Following the custom of the day, the 1793 stone was lowered onto a silver plate, inscribed with details of the event and a tribute to the first president. That cornerstone was a solid block, but the 1851 and 1959 stones had space carved inside for commemorative articles.

The 1851 mementos included newspapers, historical documents on parchment, several views of the surrounding city and $40.44 worth of coins.

An 82-pound copper box was placed in the 1959 cornerstone. Its contents included sealed messages from members of Congress, telephone books and a replica of the Bible on which Washington took the first presidential oath.

Two weeks after the cornerstone was laid, its box was opened, and a tape recording and film of the ceremony were added. The box then was sealed, its interior air replaced with helium for preservation, and returned to the cornerstone.

Unlike time capsules for which opening dates are ordained, these cornerstone deposits were intended to remain hidden as long as the building stands. Secretary of state Daniel Webster reflected that thought in his speech at the 1851 dedication ceremony when he indicated that the cornerstone contents would be "brought to the eyes of men" only when "this structure shall fall from its base."

Gen. Montgomery Meigs had similar expectations as he designed and supervised construction of the Pension Building, now home of the National Building Museum. The building's Great Hall is surrounded by 144 hollow columns. These "dry, closed spaces" struck Meigs as "admirably adapted for preservation of any documents placed in them."

So in 1883, he filled more than 20 columns with newspapers, War Department records, maps, coins and a great deal more. He thought these would "be interesting to the historians . . . of the age when the ruins of this building, like those of Egypt and of Assyria, shall be opened to the curious."

Meigs' intentions have been honored. The columns remain unopened to this day. But in 1995, a medical endoscope, developed for viewing internal organs, was used to peer inside one column.

Inserted through a small hole left by vandals, the scope provided tantalizing glimpses of remarkably well preserved newspapers. Historians are planning to use a similar endoscope and other diagnostic equipment to search for construction documents reportedly placed in columns of the original terminal of National Airport, dedicated in 1940.

Who first had the idea to decree an opening date for a time capsule? That honor apparently goes to Mrs. Charles Deihm, a New York publisher.

In 1876, she took a large safe, dubbed it the "Centennial Safe" and displayed it at the Centennial Exposition in Philadelphia. Collected inside were such items as a scroll autographed by members of the 44th Congress, photograph and autograph albums of many other famous Americans and a gold pen donated by Henry Wadsworth Longfellow.

After the exposition, Deihm took the safe on a national tour and brought it to the U.S. Capitol, where it was sealed with her instructions that it be opened July 4, 1976. During the ensuing century, the safe was stashed, at times rather unceremoniously, in various recesses of the Capitol. But it did make its date with the Bicentennial, opened in the presence of President Ford and congressional leaders.

The opened safe remained on public display in a cozy niche of the Capitol until 1984. Now it's back in storage and may reemerge when a Capitol visitors center is built.

In the Washington area, there have been numerous state and local time capsules, along with those on federal property. Fairfax County dedicated one in 1976 for the Bicentennial of the Virginia Constitution. This year, Falls Church did the same for its 300th birthday.

Then there is Ray Gallagher of Alexandria, who likes to take matters in his own hands. He fills plastic bags with newspaper and magazine clippings, takes them to partially completed new homes and hides them in walls behind the insulation -- always with permission and often with assistance of the builders.

Now 85, Gallagher has been doing this for more than 15 years. He includes in each bag a photo of himself and a brief autobiographical sketch, "so they'll know who the fellow was who put them in."

The problem with time capsules is that many don't survive. The Washington Post was keeping an aluminum, globe-shaped "Freedom Sphere" from 1954, but when it was opened in 1990, most of the memorabilia had been ruined by moisture.

Many capsules seem to disappear before they can be opened. Even some cornerstones turn out to be surprisingly elusive. There have been searches for the 1793 Capitol cornerstone, as well as those at the White House and the Washington Monument.

Records indicate that a wealth of historical material went into the Washington Monument cornerstone in 1848, including a book of poems and a publication on women's fashion.

Often, when time capsules do turn up, it's by accident. When the White House was being renovated in 1902, workers placed a marble box beneath the floor of the entrance hall. It was discovered by different workers 49 years later when the mansion was being reconstructed.

Among the contents were President Theodore Roosevelt's message to Congress, autographs of Roosevelt family members and the label from a whiskey bottle.

Washington writer Lester A. Reingold invites readers with interesting stories about time capsules to contact him at LReingold@aol.com.

Care to make your own time capsule? A good source of guidance is the Smithsonian Institution's Conservation Analytical Laboratory on the Web at http:// simsc.si.edu/cal/timecaps.html.

To maintain a record of your creation, you can register it with the International Time Capsule Society at http://www.oglethorpe.edu/itcs.

CAPTION: A fresco shows Washington laying the cornerstone of the U.S. Capitol building in 1793.