There was one studio session wherein John Lennon accidentally took LSD, luckily leading to one of the Beatles' best psychedelic songs.

Blasting on his car stereo were songs from “Free LSD,” the quartet’s latest album, so Morris could reacquaint himself with the record’s far-out lyrics of alien invasions and mind control.

The Beatles were no strangers to drug culture. Find three of the trippiest Beatles songs inspired by LSD, below.