People wander around the old cemetery in small knots, taking care not to stumble over a toppled headstone or unexpected dip in the earth. One group pauses before a tombstone featuring a plump Cheshire cat with a mile-wide grin, while a second clusters around a shiny, black accordion monument proclaiming, "Music is the answer." In Mausoleum Row, bees buzz in and out of the hives atop the stone structures, dutifully making honey for packaging under the gift shop's "Rest in Bees" label. And near the chapel, a bevy of workers set tables in preparation for the medieval-themed outdoor wedding reception that will begin in just a few hours.

It's just another day at Congressional Cemetery in Washington, D.C., the busiest, cheeriest burial grounds I've ever seen. Some 20,000 visitors meander through its 35 acres annually, a fraction of the 3 million that flock to Arlington National Cemetery, 7 miles due west. Arlington is a must-see site, for sure. But my mission on a recent trip was to discover lesser-known attractions in our nation's capital. And of the five gems I discovered, Congressional Cemetery, in the Capitol Hill neighborhood, tops the list.

In 1807 — more than 50 years before Arlington's founding — eight locals saw the need for a burial ground in America's fast-growing capital city and created Congressional Cemetery. Over the next two centuries, a wide range of people were interred here, from regular citizens to notables such as Civil War photographer Matthew Brady; John Philip Sousa, conductor of the U.S. Marine Band; J. Edgar Hoover, the first director of the FBI, and more than 75 members of Congress. U.S. Vice President Elbridge Gerry also rests in relative peace here; he signed the Declaration of Independence and, as governor of Massachusetts, consolidated Federalist Party voters into a few newly drawn senatorial districts, resulting in the practice dubbed "gerrymandering."

During the late 20th century, nearly 200 years after Congressional Cemetery's inception, the graveyard fell into disrepair. Grass grew waist-high, tombstones crumbled and unsavory characters moved in. Eventually, local residents joined forces to resurrect the cemetery, by then a National Historic Landmark, mainly through the creation of the K-9 Corps. Under this inventive program, still in existence, locals pay an annual fee to walk their dogs on the grounds off-leash. The constant presence of dogs and their owners keeps away the ne'er-do-wells, while the annual K-9 Corps fees — now coupled with donations, grants, congressional appropriations and proceeds from gravesite sales — provide income to maintain the grounds.

Today, the cemetery is alive and thriving. Visitors can stroll through the grounds daily from dawn to dusk to scope out its intriguing collection of tombs, which come in a variety of styles, materials and forms. Volunteer docents, often wearing shirts proclaiming "We will talk about you after you're gone," give free tours every Saturday from April to October. Themed walking-tour brochures show you where to find the gravesites of FBI agents and prominent members of the LGBT community, among other groups. Every Nov. 6 — Sousa's birthday — the U.S. Marine Band marches to his tomb, plays one or two of his songs, then marches out.

Locals recommend coupling a visit to Congressional Cemetery with a stop at local cafe Ted's Bulletin, where you can purchase homemade Pop Tart-like treats or indulge in a boozy milkshake. Ted's sits one mile from the cemetery and just a block from the Eastern Market Metro (subway) stop.

If all of this sounds like your kind of fun, you'll probably enjoy these four other lesser-known spots.

DEA Museum

Just across the river from all those busy Smithsonian museums, in Arlington, Va., lies a small gem. The free Drug Enforcement Administration Museum, spotlights the problem of drug abuse in the U.S. The compact museum, which can be explored in about an hour, traces the various drug epidemics that swept the U.S., from opium and cocaine in the late 19th and early 20th centuries, to marijuana and psychedelics in the 1960s, to today's prescription opioid crisis.

The museum contains a few interactive components, information about the relationship between drugs and organized crime, and an extensive display about little-known Harry Anslinger, first commissioner of the Federal Bureau of Narcotics, who served from 1930 to 1962.

Kilroy Was Here

Many, if not most, Washington visitors head for the stately World War II Memorial, on the National Mall about a mile east of the Lincoln Memorial. But few discover its two Kilroy etchings, tucked away on the memorial's back side. The engravings — an intentional, fun part of the memorial's design — depict a bald man with a long nose peeking over a fence, along with the words," Kilroy Was Here."

While there are various stories about the origins of this famous World War II-era doodle, historians say the most credible begins with a man named James Kilroy. Kilroy was an American rivet inspector during WWII who scribbled "Kilroy Was Here" in nooks and crannies of new ships. Sailors who eventually boarded the ships and discovered his inscriptions found them amusing. Soon, they began scrawling the same phrase in other odd, hidden spots as a joke.

Later, when American troops traveled overseas, they saw a similarly ubiquitous sketch of a bald man peering over a fence. These were the works of Brits, who were drawing the bald man everywhere. Soon the phrase and sketch were joined, then inscribed wherever Allied troops gathered. Adolf Hitler supposedly thought Kilroy was a famous spy, while Japanese troops are said to have reported the mystifying inscription to senior intelligence officers.

U.S. National Arboretum

The 446-acre National Arboretum features 9 ½ miles of winding roadways that pass impressive collections such as the National Herb Garden, the Flowering Tree Walk and the Fern Valley Native Plant Collections. But the main reason for a stop in this northeast D.C. refuge is to stroll among the National Capitol Columns.

Majestically standing on a natural knoll surrounded by more than 20 acres of open meadow, the 22 Corinthian sandstone columns were once part of a set of 24, sited in the U.S. Capitol's East Portico in 1828. Twenty-eight U.S. presidents, from Andrew Jackson (1829) to Dwight Eisenhower (1957), were inaugurated in front of them. But there was a problem early on in their lives.

In 1864, when the Capitol's iron dome was finally completed and set in place, it appeared as if the pillars could not support it. This visual mismatch occurred because the dome was built much larger than the designer intended. Experts decided to solve this disorienting problem by removing the columns and adding on to the East Portico, which would result in a more balanced-looking structure. But it took nearly 100 years for this to actually happen.

After the columns were removed and the addition constructed, the columns sat in storage until 1984, when they were restored and moved to the National Arboretum. The stately columns, arranged in a rectangle, are a beautiful sight. The foundation merits inspection, too; it's crafted from old steps that once graced the Capitol's east side. Some of the steps still sport their old quarry identification numbers.

Bonus: The arboretum is also home to the National Bonsai & Penjing Museum, which includes a bonsai that survived the atomic bombing of Hiroshima and some trees more than 300 years old.

Franciscan Monastery

A trip to the Franciscan Monastery of the Holy Land in America, in northeast Washington, resembles a mini-visit to biblical locales. The Catholic Church's Franciscan friars have been charged with protecting the Holy Land and its Christian shrines for 800 years. So when the Franciscan Order decided to create a monastery in Washington, D.C., the founder had an inspiration: incorporate replicas of Holy Land shrines.

If you take one of the monastery's free daily tours, you'll be able to see carefully crafted replicas of sites such as the Stone of Unction, where Jesus' body was anointed after his death; the Edicule covering Jesus' tomb in Jerusalem's Church of the Holy Sepulchre; Calvary, where Jesus was crucified; and the manger in Bethlehem, where Jesus was born.

The monastery is also home to ornate, century-old gardens, which you're free to roam. The gardens contain replicas of sacred shrines, as well.

Melanie Radzicki McManus (melaniemcmanus.com) is a freelance writer focusing on fitness and travel. She lives near Madison, Wis.