YOSEMITE NATIONAL PARK, Calif. — On their 19th day of climbing, Tommy Caldwell and Kevin Jorgeson reached the summit of El Capitan’s Dawn Wall, completing a quest that included years of planning and that many considered the most challenging rock climb in the world.

Dozens of family members and friends greeted the climbers when they reached the top at 3:25 p.m. on a cloudless day.

They are the first to free climb every vertical inch of the 3,000-foot Dawn Wall in a single expedition, long considered impossible, using only their hands and feet to pull themselves up. Ropes were merely safety devices to break the occasional fall. By virtue of its scale and difficulty, the climb is considered by some to be the most difficult ever accomplished.

The view was stunning. What was less clear was just what it was that they accomplished.

El Capitan is hardly unassailable. Its face was first climbed in 1958, and it has been crisscrossed by countless climbers using roughly 100 known routes. With its summit a mere 7,569 feet of elevation, it is no Mount Everest or Mount McKinley. Thousands of visitors from around the world hike the eight steep miles to its top each year, including several who left before daybreak Wednesday to greet the climbers.

But that is part of what made this expedition monumental — El Capitan’s familiarity. It is one of the best-known pieces of granite in the world, majestic and monolithic, causing crane-necked, open-mouthed gawkers to stand at its base and drivers in Yosemite Valley to veer off the road.

That accessibility was key to building fascination with the quest.

The entire climb was visible to anyone who wanted to watch through binoculars or long camera lenses while standing in El Capitan meadow. And in recent days the assembly grew to witness history unfold high above, some bringing camp chairs and nibbling on meats and cheeses. From the wall, the climbers communicated through text messages and social media. Fans cheered success, and the climbers could hear it a moment later.

That was the magic that turned the quiet quest of two quiet men into a worldwide spectacle — an event both unimaginable and watchable. There was no mystery, but plenty of suspense.

“This is just amazing, really beautifully amazing, like a 4-minute mile or a sub-2-hour marathon or Tiger Woods destroying every single major for a year or something, just off the charts awesome,” Will Gadd, an elite mountain sports athlete, said in an email message Tuesday.

For Caldwell, 36, from Estes Park, Colorado, it was a goal that he could not shake since he first seriously conjured the idea a decade ago. It became his life-bending quest, a personal Moby Dick. Could every inch of the blank, vertical face of the Dawn Wall be climbed with nothing more than bare hands and rubber-soled shoes? He was not sure. He never was, really, until Wednesday.

“From the outside it was starting to look like a Hemingway novel or something, an unresolvable quest,” said Gadd, who has known Caldwell for many years.

Jorgeson, 30, from Santa Rosa, California, learned about Caldwell’s vision in 2009, and asked if he wanted a partner. Each year since, the two have spent weeks and months, mostly in the fall and winter, attached to the Dawn Wall, scouting holds, practicing pitches, imagining how to do it all in one push from the valley floor.

El Capitan is the height of three Empire State Buildings stacked atop one another, but with infinitely fewer, and smaller, things to hold on the way up. The climb was divided into 32 pitches, or sections, like waypoints on a dot-to-dot drawing. When one pitch was successfully navigated, the climbers stopped and prepared for the next. Much of the work was done in the cool of the evening, when hands would sweat less and the soles of their shoes had better grip.

Some pitches were well more than 100 feet straight up the rock, while others were sideways shuffles to connect two vertical pitches. One required a dyno, or a jump from one precarious hold to another. Falls were not unusual; Jorgeson needed seven days and 10 attempts to navigate the horizontal traverse of Pitch 15, unexpectedly slowing the expedition, which was blessed by an uncharacteristic stretch of dry weather.

Few, if any, thought the Dawn Wall could be free climbed, using just strength and guile, not ropes and equipment, for upward propulsion. Earlier attempts by Caldwell and Jorgeson had been aborted by bad weather, injuries and an inability to get past certain pitches.

Not this time. After a summit celebration, Caldwell and Jorgeson were eager to return to the valley floor for a bigger celebration, and the chance to soak in both a warm shower and whatever adulation awaited once they returned to the view of anyone who wanted to watch.

Soon, they will be back over the edge, headed down, and the top of El Capitan will be alone and quiet again.