The Union built Fort Ward to defend the capital city from Confederate hordes; a few years later, no hordes having struck, the Union sold it for scrap. A century later the locals restored the fort, and the hordes finally swept over the battlements.

The invaders wield Frisbees and worship the sun on 40 acres of grass and flowers where once was dust and mud. Fort Ward Park, straddling an Alexandria knoll, seems ready-made for a peaceful afternoon. And there's also a bit of history among the picnic tables and trees.

The fort, which occupied Confederate territory in sight of Southern soldiers, was one of about six dozen the Union built -- hurriedly, after the disaster at Manassas in July 1861 -- to protect the District of Columbia. Its mission, from late 1861 till the Civil War's end in 1865, was to keep the Alexandria-Leesburg Turnpike, now State Route 7, and the Little River Turnpike, now State Route 236, safe for Yankees.

At this it was wildly successful: life at the fort was an unrelieved bore.

"From the letters and diaries we've found, we can see there were a lot of drills, artillery practice, cleaning guns and standing guard, of course," says Wanda Dowell, curator of the Fort Ward Museum, a colonnaded replica of Alexandria's Union headquarters, next to an officers' hut; the two not far from the ceremonial gate. "The soldiers also made trips to Washington -- to the Smithsonian or to the Capitol to hear Congress debate -- and even to Mount Vernon. To a certain extent they played tourist."

One defender of Washington, William Frothingham, wrote to his brother in March 1862, "Soldiering is simple work. Ditching, wheeling barrow in fortifications, cutting timber, cooking, walking in mud, rain and darkness -- these are the occupations of this life of glory. The fighting is a rare pastime and only a part ever engage in it."

Armed with sodas and tanning lotion, you now can stroll where a thousand or more miserable men in woolen jackets braved sweltering summer days: past restored earthen shelters, along rocky trenches and clear to the old fort's northwest bastion.

The meticulously restored bastion, with three replica cannon, is the fort's most impressive feature. It's not hard to see why the garrison never needed to fire an angry gun.

The tents that sheltered workaday soldiers are long gone, but the simple frame officers' hut -- "rather elegant quarters," reads the legend -- gives a taste of fort life. Copied from a Matthew Brady photograph, the building holds a spartan cot, water pitcher and washbasin, a table full of medical supplies and a copy of Harper's Weekly: just the thing for a midday snooze.

The museum is in unsettling contrast to the pastoral doings outside. In the compact display area sit weapons and uniforms from the Fort Ward collection, a chip of petrified hardtack, period furniture, an 1850s-vintage "new-improved" portable Lambly's copying machine taken from a martyred Yankee lieutenant, instruments and sheet music (like a ditty by George F. Root called "Just Before the Battle, Mother"), sketches from wartime artists (Edwin Forbes' "Fall in for Soup" catches both the languor and the terror of the occasion) and examples of wartime journalism.

There is, for instance, the July 2, 1863, issue of the Vicksburg Daily Citizen, reporting General Ulysses S. Grant's great siege. "The Yanks outside the city are considerably on the sick list," the lead story begins. "Fever, dysentery and disgust are their companions, and Grant is their master."

In the lower right-hand corner, though, sits an unobtrusive "NOTE" dated July 4, 1863: "Two days bring great changes. The banner of the Union flies over Vicksburg. Gen. Grant has 'caught the rabbit;' he has dined in Vicksburg and he did bring his dinner with him."

Then, in a couple of glass cases, there's a special exhibit called "Medical Care for the Civil War Soldier" -- not for the faint of heart. What with the bonesaw, forceps, suture needles and scalpels, plus an implement called a tenacula ("hooked instrument for lancing and taking up arteries"), it's a wonder any of the wounded recovered. The display will stay through the summer. FORT WARD PARK -- At 4301 West Braddock Road in Alexandria, off the King Street Exit of I-95, the park is open 9 to sunset daily. The museum is closed Mondays, open Tuesday to Saturday 9 to 5 and Sundays noon to 5. It offers regular Sunday programs, including a presentation of camp life and drills, from 1 to 4 on May 30; a lecture on the navy at 2 on June 6; concerts of Civil War music on June 13 and June 20, both starting at 2; and, on August 8, a reenactment of the Battle of Fort Stevens, featuring 400 "soldiers" from all over the East Coast. Thursday night concerts, all at 7:45, have started in the park's amphitheater. Call 838-4848 for details.