Scientist Bernard Quatermass has his first glimpse of the Planet People, a hippie/punk cult drawn to megalithic stone circle sites, in this clip from the 1979 series (also released internationally as a movie) The Quatermass Conclusion.
On a personal note, while I have no other memory of having seen this show, I do recall this creepy nursery rhyme, which was devised by scriptwriter Nigel Kneale and which seems, within the Quatermass universe, to have a hypnotic power for young folk, enticing them to join the Planet People:
Unfortunately for the Planet People, the rapture to a paradisical planet that they are hoping for never comes to pass; their gatherings at stone circles in fact see them incinerated by an extraterrestrial energy beam, harvested by an alien species hungry for human proteins.