It was in January of that year that up to 30,000 people gathered in San Francisco's Golden Gate Park.
"One of the things we did was we got together an event called 'The Human Be In' and it went off pretty damned well," Grateful Deal guitarist Bob Weir told Sunday Morning correspondent John Blackstone. "You know, we were starting to feel our oats and starting to think of ourselves as a movement."
It was at the Human Be In that Timothy Leary gave the movement a motto: "Turn on, tune in, drop out." The timing was right for a generation beginning to come of age.
"There was this big demographic bulge that happened from the baby boom," Weir said. "So there were just a lot more kids. And so there was a sort of infusion of youth energy."
That youthful energy was on full display a few months later at The Monterey Pop Festival. For three days in June, 200,000 people came to listen. There had never been a festival like it.
Many performers who would shape rock for years to come — like The Who, Simon and Garfunkel, Jimi Hendrix, Jefferson Airplane and Janis Joplin — made their first big appearance. The bands performed for free. Those who came to listen paid just $1, if they paid anything. The Summer of Love had begun.
Gitlin has written extensively about the '60s when the war in Vietnam, the struggle for civil rights and a growing women's movement turned many into activists.
"So in that setting, while the Summer of Love was odd, it wasn't that odd," he said. "Because the whole period was odd — the whole period was full of thousands of people doing remarkable things, especially young people."
"It felt like being at the crest of a wave," Judy Goldhaft, who belonged to a group called the Diggers.
She knew exactly where that wave was cresting — in the San Francisco neighborhood of Haight-Ashbury.
"My friends have said, 'You'd wake up in the morning and you'd never know who was on your living room floor sleeping.' They were packed."
The Diggers were a group of actors, artists and anarchists who saw Haight Ashbury as a place where they could transform society.
"And we felt that we could do many things, many impossible things, we were capable of doing them," Goldhaft said.
"We approached newcomers into the Haight-Ashbury and establishment with the proposition, everything is free," Peter Berg, another Digger, said. "So I would say to a policeman, 'Why don't you put 'free' in front of something that you want to do? And then do it?' Become a free cop. What would a free cop be like? What would a free banker be like? What would a free fireman be like?" That was our approach. It was fun-loving."
The Diggers ran a free store. They gave away free food. On Haight Street there was a free clinic and plenty of free expression. The young quickly embraced free love. And the neighborhood rock bands gave free concerts.
"People would pony up and we'd rent a flatbed truck and put our equipment on it and take it down to the panhandle to the park," Weir said. "And set up and play."
"Rock music became, for the counterculture, what the newspaper had been for the straight culture: It became the way that people talked to each other and sent the word out," said Sunday Morning music critic Bill Flanagan of MTV. "As the word got out, newspapers and TV across the country picked up the story of young people flooding into Haight Ashbury. All those things sort of came together and created the first great rock marketing event, created a kind of nationwide notion that everyone should leave their parents, get in a Volkswagen bus, and head to San Francisco."
The more that was written, the more people came.
"I once described 1966 as the Summer of Love; 1967 was the summer of a million people," Goldhalf said.
"The media, to a large extent had created this 'hippie' who was a person making a 'V for Victory' sign with a silly grin, and wearing 50 buttons that said this and that. That wasn't what a lot of us were doing," Berg said.
For outsiders the "hippie" life style could seem as foreign as some distant culture. When CBS sent Harry Reasoner to Haight-Ashbury in 1967 he was clearly disturbed by what he found:
"There's the real danger that more and more young people may follow the call to turn on, tune in, drop out," he said then.
One stop for the CBS cameras was 710 Ashbury Street, the home of the Grateful Dead. Weir was 20 years old and tried to offer reassurance that there was nothing to fear in what was happening here.
"That the people that live in the community and play around with dope and stuff like that they don't have wars, you know, and they don't have a lot of the problems that larger society has," he said in 1967.
Today, Weir says he knew back then that he and his friends were scaring the older generation, and they were having fun doing it.
"I mean, we weren't dangerous," he said. "We knew that. And if they didn't, well, sooner or later they'd figure it out."
Soon enough though, things started to get dangerous in Haight-Ashbury. Marijuana and LSD had long been part of the scene. But as the kids poured in in the summer of '67, the drugs got harder and more hazardous.