You’ve surely seen the bells, driving along the 101 or maybe even the 5 Freeway.

They mark the historic road known as El Camino Real – so historic, in fact, that it’s been designated California Historical Landmark No. 784.

Most of those mission bells are now exact copies of the 1906 first versions, made from their original molds. But they only mark a fraction of what there is to see on this “royal road,” or the “King’s Highway,” that supposedly once connected the Spanish missions in what was then known as Alta California.

You’ll also find El Camino Real connecting landmarks associated with the founding of various SoCal cities – including founders’ ranches and historic presidios (like Santa Barbara and San Diego) and other military installations.

Like Route 66, tracing its path isn’t an exact science – and there was no one singular “royal road.” Travelers carved out alternate paths and spur trails that branched off of the main road. Sometimes they were as narrow as a footpath, and the “traffic” consisted of pedestrians (padres, missionaries, soldiers), horses, mules and wagons.

So, following El Camino Real becomes a kind of treasure hunt for historians, cartographers, and roadtrippers – leading them to diverge off of the “official” commemorative road to see what treasures may lie hidden in the hillsides of Southern California.

And you can, too.

From Ventura County to San Diego County, here are five of the lesser-known historic sites that are within a stone’s throw of El Camino Real – and just as historic as the missions that it once connected.

1. Leonis Adobe Museum, Calabasas

In the West San Fernando Valley community of Calabasas, you’ll find Los Angeles Cultural Monument No. 1, the Leonis Adobe Museum. Standing along Calabasas Road in the shadow of the Ventura Freeway – right where El Camino Real used to run – its centerpiece is an adobe house built back in 1844. Historians’ best guess is that it served as a stagecoach stop on El Camino Real, but it was made famous by Basque immigrant Miguel Leonis, who became known as the "King of Calabasas" from his real estate holdings and other sources of wealth. With his wife Espiritu Chijulla, the daughter of a Chumash chief, Leonis bought the adobe and expanded it into the two-story Monterey-style mansion that currently stands, with its characteristic wraparound veranda. But it only exists today because it was saved from the wrecking ball in 1962 by a preservation campaign!

Also saved was the circa 1912 barn, which has been moved – twice! – to accommodate construction of the 101 Freeway. Wander the grounds to admire the windmill (used to pump water) and tank house (used to make wine) and visit with the livestock and other animals of an authentic ranch yard circa 1880s.

The museum itself was established in 1966 – now, the parcel of land that the adobe sits on has also become a repository of other saved buildings. That includes a surviving portion of the historic Plummer House, relocated to Calabasas from its original location in West Hollywood’s Plummer Park in 1983. It now serves as the museum’s visitor center and gift shop, which are open Fridays, Saturdays and Sundays until 4:00 p.m. Check the online calendar for official hours and holiday closures.

2. Rancho Calleguas and Adolfo Camarillo House, Camarillo

The original Camarillo ranch extended all the way over past where the 101 Freeway runs now, and more or less alongside where El Camino Real connected Mission San Fernando and Mission San Buenaventura. Juan Camarillo had bought 10,000 acres of the former Mexican land grant, known as Rancho Calleguas, in 1876. The historic house that sits on that spot now was once the center of activity of cattle, citrus orchards, walnut trees, lima bean fields, and the mules that hauled the lima beans. Juan’s oldest son Adolfo eventually leant his name to the town of Camarillo, which was created out of large parcels of land given to Southern Pacific Railroad.

He must've done good business, because the former residence of this prominent Californio is one of the nicest ranch houses you’ll see in SoCal. In fact, to call it a "ranch house" is to diminish its grandeur. It's really a Victorian mansion, with 12-foot ceilings and 14 rooms, built in the Queen Anne style by the architecture duo Herman Anlauf and F. P. Ward. Although the 1892 home has undergone substantial renovation and restoration, it still has its original tiled fireplaces, as well as a number of historic artifacts – including Camarillo's own silver saddles in the ranch office and throughout.

Camarillo Ranch has been and still is ground zero for the prized "Camarillo White Horses" (born white with pink skin), which may be even more famous than Camarillo himself! They were so popular that they marched in the Rose Parade and the opening ceremonies of the 1932 Summer Olympics in L.A., but most of them were auctioned off in the 1980s when Adolfo's daughter Carmen died. Still, a couple dozen of the descendants still exist and occasionally appear at the city-run park.

3. Casa Romantica Cultural Center and Gardens, San Clemente

Located midway between Los Angeles and San Diego, San Clemente is just six miles south of Mission San Juan Capistrano, located on the former Rancho Los Desechos. In the early 20th century, El Camino Real was the only way to get in or out of this beachside Spanish Colonial Revival resort town. Back then, it was considered the “middle of nowhere.” Although this “Spanish Village By the Sea” is now far more accessible by other routes, El Camino Real still runs right through the middle of town, past all the contributions made by San Clemente’s co-founder, Ole Hanson. Two hundred of those white stuccoed, red tile-roofed buildings – no taller than four stories, except their tower – remain today. Much of the original village, whose theme Hanson “borrowed” from Santa Barbara, has been lost.

Although Hanson and his family maintained permanent residence in Los Angeles, it’s here that he commissioned architect Carl Lindbom to build a vacation home – the 15-room “Hacienda San Clemente,” which has been preserved and is open to the public. It was completed in 1928 in the Spanish Colonial Revival style – with a tiled solarium room (with Italian ceramic fountain) and an octagonal reading room surrounding a central courtyard – but the Great Depression brought with it a bank foreclosure in 1934. After changing hands many times, the mansion was reborn in 2003 as Casa Romantica.

Step out onto the ocean porch and look out at the San Clemente Pier in the distance. The blufftop location provides cool ocean breezes and plenty of sunshine for the 2.5 acres of coastal gardens. The gardens include the yucca planted by Ole Hanson himself in 1927 and a prickly pear cactus that’s original to the home, as well as many newer and water-wise plantings. The home and gardens are both accessible with a small admission fee Tuesdays through Thursdays from 11:00 a.m. to 4:00 p.m. and Fridays through Sundays from 10:00 a.m. to 2:00 p.m. (closed Mondays). Check the online calendar for a schedule of programs in arts, music, history, horticulture and literature.

4. Heritage Park Village Museum, Oceanside

Walking distance from Mission San Luis Rey and just outside the boundaries of Camp Pendleton is a permanent outdoor museum that first opened as part of the nation's bicentennial celebration in 1976. Heritage Park Village Museum features Oceanside historical landmark buildings such as the Libby Schoolhouse, The Blade Newspaper Antique Printing Museum, the Payne-Johansen House, the Blacksmith Shop & Livery Stable, the Portola Inn, the old-time post office, the old jail and a doctor’s office.

Now relocated to their new home in a manicured park, these original structures date back to the turn of the last century – the park itself gives a glimpse into the history and culture of Oceanside circa 1885 to 1920. Though that was decades after the California Mission Period, its present-day proximity to El Camino Real tells us plenty about the evolution of the area, from the trail used by the Franciscan Padres between the missions to one of the earliest roads used by soldiers to protect this area of Southern California.

Heritage Park is free and open to the public Wednesday through Sunday from 9:00 a.m. to 4:00 p.m. Take a guided tour on a summer weekends, or attend its annual Heritage Park Day event in early May.

5. Leo Carrillo Ranch Historic Park, Carlsbad

In the North San Diego County city of Carlsbad, you’ll find that much of El Camino Real has been developed into strip malls and other shopping plazas, as it runs along route S11 past a country club, schools, housing developments and the Palomar Airport. But less than two miles east of this historic trail – down Flying Leo Carrillo Lane, just off of Carrillo Way – you'll find the "Flying L" Ranch of movie and TV actor Leo Carrillo, whose brand features his initials and a pair of wings.

At 27 acres, Leo Carrillo Ranch – now a historic park owned and ran by the City of Carlsbad – is considerably smaller than it was in Carrillo's time, though it still contains structures like the old caretaker's quarters. And the park office? Make it your first stop, as it acts as a primer for anyone not so familiar with Leo Carrillo, the cowboy of the big and small screen who’s most famous for portraying the desperado sidekick Pancho on "The Cisco Kid."

Carrillo purchased the property in 1937, built 18 additional structures and renovated what was extant. Carrillo returned The Hacienda, which had been built of adobe but later covered with wood, to its original splendor, roofed in red terra cotta tiles. Leo's bedroom still features fabulous Western-style furniture custom-made by Barker Brothers. The throngs of people who attended Carrillo's regular rodeos and other events on the ranch found themselves fed by an outdoor kitchen and intoxicated by the pool’s cabaña and the cantina by the carriage house. And there’s lots more to see, too.