Thousands of motorists and spectators lined the hillsides along the Palos Verdes Peninsula coastline in the vicinity of Bluff Cove on a sunny Sunday afternoon in the early 1920s, and what they witnessed truly was extraordinary.

On that day, Oct. 21, 1923, engineers from the Hercules Powder Company set off a fuse that detonated 100,000 pounds of black powder and 10,000 pounds of dynamite.

The resulting blast sent an estimated 100,000 cubic yards of earth and rock tumbling into the ocean. More than 300,000 cubic yards eventually would be cleared from the area.

“When the explosion came, it could be heard for miles and the earth trembled for a moment as if shaken by an earthquake,” according to a story the next day in the Los Angeles Times.

What sightseers had viewed was the clearing of a hillside for the Douglas cut, an earthmoving feat that would allow for the construction of a continuous roadway along the length of the Palos Verdes shoreline. (It took its name from a surveyor’s stone labeled “Douglas” that had been placed nearest the the land being excavated.)

Back in February 1914, Peninsula landowner Frank A. Vanderlip and his financial backers had announced plans to build a coastal highway that would follow the oceanfront from Redondo Beach to the Miraleste area west of San Pedro. It would expand and extend the road then known as Granvia La Costa, and now known as Palos Verdes Drive West.

The plan, announced years before lots in the area were sold to the public, would open the isolated Peninsula to visitors and traffic, due to its scenic vistas. The developers also believed that it would become part of the statewide coastal highway being planned by transportation authorities.

The Highway 1 project then was in its infancy. Its first segment, linking Ventura and Santa Barbara, had been completed a year earlier in 1913.

Following the big bang at Douglas cut, work continued on the Coast Road, sometimes called the Coast Highway. A second eight-mile segment from Lunada Bay to Miraleste was completed in 1926 at a cost of $400,000, with the cost of the entire project estimated at $750,000.

The roadway opened to the public on July 4, 1926. Its completion was cause for celebration, and a special one was planned for its official dedication held a few weeks later on July 31.

An estimated 5,000 people joined in a parade of about 1,200 automobiles that traversed the new road’s length from San Pedro to City Park (now Veterans Park) in Redondo Beach. The road was still dirt at the time, with plans to surface it with macadam after the fall rains.

The opening of the new coast highway had an immediate effect on home sales on the Peninsula. Real estate agents reported a 100 percent increase in sales for the year 1926, attributing much of it to increased public interest following the July highway opening.

One plan to link the scenic highway with Hollywoodland (as it was then known) via Hawthorne Boulevard never came to fruition. The Hollywood-Palos Verdes Boulevard was envisioned as a 225-foot wide “pleasure boulevard” linking the two areas.

It wasn’t the only highway plan that didn’t come to pass. In the late 1920s, government highway engineers and planners nixed the idea of making the Coast Highway part of the California Highway 1 project.

As 1929 maps indicate, they opted instead to swerve Highway 1’s route inland between Redondo Beach and Seal Beach, following the existing Wilmington-Redondo Road’s pathway through the South Bay before dipping back down to the coastal area in Seal Beach.

It would be several decades before the Highway 1 project officially was unified and completed as State Route 1 in 1964. It stretched from its southern terminus at Dana Point to Leggett in Mendocino County in the north, a distance of 655.8 miles, making it the longest highway in California.

Still, building the coastal roadway proved to be essential for the Palos Verdes Peninsula. Opening up the area brought access to one of the most beautiful scenic drives in Southern California, which resulted in enhanced real estate values and brought assests including the late Marineland, Terranea, Trump National Golf Course and other attractions to the area.

The eventual completion of the Palos Verdes Drive circle with the building of Palos Verdes Drive North in the 1930s made it possible to circumnavigate the entire Peninsula area via P.V. Drives North, West, South and East and North.

Taking in its wealth of natural beauty on a leisurely Sunday afternoon drive remains as well worth doing today as it was decades ago.

Sources:“California Highways” website, “California State Route 1,” Wikipedia.org, Daily Breeze files. Images of America: Palos Verdes Estates, By John Phillips, Arcadia Publishing, 2010.. Los Angeles Times files. “The Palos Verdes Story,” by Delane Morgan, Palos Verdes Review, 1982.