It was during the third and final afternoon of Woodstock that Jo Mueller registered one of her fondest memories from the historic 1969 music festival.

English singer Joe Cocker was on stage while 19-year-old Mueller, along with hundreds of thousands of others, danced and swayed to the songs, particularly Cocker’s cover of The Beatles’ “With a Little Help From My Friends.”

Overhead, helicopters flew over the crowd, one of them catching Mueller’s eye.

“What I remember is Joe Cocker was up there ... singing his brains out, (and) there was a helicopter that came over the crowd and actually dropped flowers,” said Mueller, of Joplin, the former executive director of Spiva Center for the Arts.

It’s a memory she has cherished for decades.

Aquarian Exposition

Billed as an “Aquarian Exposition” of peace and music, the festival that defined a generation turns 50 this week. Held Aug. 15-18, 1969, at a 600-acre dairy farm near Bethel, New York, it featured 32 live performances — all outdoors, some in the rain — atop a stage flanked by scaffolding.

Mueller, a Joplin High School graduate working in Boston as part of a college-sponsored work-study program at the time, first heard about Woodstock via colorful flyers and radio ads.

“Like lots of people on the East Coast, you heard about this thing,” she said.

Excited, she called her good friend, Jane Pickett Sharon, who was attending what was then known as Missouri Southern College, begging her to go too.

“I told her there was going to be this thing — music, all these bands, all this stuff. She asked her mom. Her mom said: ‘Well, if Mary Jo’s going, and you’ll go with her, then I think it’s OK,’” Mueller said with a chuckle. “They always thought I was always so quiet and so good.”

She added: “But I was a hippie at heart.”

Sharon, then 18, flew to Boston, and soon after, the pair, along with four other friends including a U.S. Army Green Beret, hopped into a Volkswagen Beetle and drove from Boston to Bethel.

“We just drove and drove and drove until pretty soon all the traffic came to a standstill,” Mueller said.

Traffic jams leading into Bethel from all compass points have become the stuff of legend.

“It was like four lanes of traffic on a two-lane road, all going one way,” Mueller said.

Even here, before the festival began, Mueller said she sensed something all Woodstock attendees would talk about for decades to come — a sense of overpowering peace, love and friendship among complete and total strangers.

“There were state troopers (directing traffic) and people much wilder than we were playing guitars, but everybody was just so nice to one another,” Mueller said. “Even the troopers, they were smiling. Everybody was being polite.

“That was kind of the thing that gave me the impression that everybody could come together,” she added.

Woodstock begins

On the morning of Aug. 15, they found a spot to park their VW and hiked more than 3 miles to the festival site, placing sleeping bags on a spot halfway up the hill, just left of the stage. A nearby booth sporting large flags served as a marker for their chosen spot amid the mass of humanity that poured into the event.

Sharon laughed as she said she expected Woodstock to be “a couple of days with a few bands.” When she got there, the “immensity” of the festival hit her — three days, more than 30 bands and a crowd that grew to several hundred thousand people.

“At that point in my life, I was young enough not to be nervous. ... Everybody was just enjoying themselves,” Sharon said. “Some in different ways than others.”

“We really didn’t stray too far,” Mueller said. “We kind of sat there with our mouths open.”

Both said they had never seen anything like the people sprawled out across the grass before them, taking up every inch, some sleeping, some sitting, some standing, some dancing.

“Honestly, people think that I’m lying about this, but we didn’t do any drugs,” Mueller said. “And there wasn’t any reason to do any drugs because the contact high — emotionally — was just so high. It was just a very opportunistic time to see all of the people there.”

There were no fights, no violence — just a willingness by one and all to help out others, Mueller said.

“Really the only thing that you heard of a negative nature were announcements: ‘This color of acid, avoid it; do not do this, it’s not good for you,’ (or) telling guys to get down off the scaffolding because there was a lot of rain and they were afraid of lightning.”

Neither Mueller nor Sharon strayed far from their little corner of Woodstock, though they did venture over to the area where food was being served, dubbed the Hog Farm. But they did not visit the infamous Fillippini pond, where you could find people skinny dipping during all hours of the day and night, nor did they go anywhere near the unauthorized area where drug dealers congregated.

But the music — “Oh my gosh,” Mueller said with a grin. With the exception of sleeping through the Grateful Dead during the late evening on Day 2, they saw some of the highlight acts — Santana, Creedence Clearwater Revival, Janis Joplin, Sly and the Family Stone, and The Who.

“The music was incredible,” Sharon said. “The music went on and on, and when there wasn’t live music ... people were enjoying visiting one another. You didn’t know who they were or where they were from, you just enjoyed it all, everybody being there and enjoying themselves.”

The two stayed for the most memorable act of all, when Jimi Hendrix performed a two-hour set at sunrise on Monday, Aug. 18, including his rendition of “The Star-Spangled Banner.”

“You would be dog tired and then somebody would come on and then everybody would be on their feet at 2:30 in the morning,” Mueller said.

“We knew (Woodstock) had impact,” she said. “We knew it while it was happening. It was just too incredible. We could even sense it before we even got there. The feeling was, during this thing, it felt like this group of people had so much love and community ... that the world, that these people, could change the world. I thought it was entirely possible to bring about change (for the good).”