Even legends have to start somewhere.

For the Doors — the psych rock pioneers who pushed the limits of minds and music with tracks like “Light My Fire,” “Love Me Two Times” and “L.A. Woman”— it can all be traced to the London Fog on Los Angeles’ Sunset Strip. Just months after forming, the nascent group was offered a residency at the down-at-the-heels club in early 1966. Having played little more than the odd college party for their UCLA film school friends, the London Fog became the Doors’ home base and testing ground. Six nights a week, from 9 p.m. to 2 a.m., singer/poet Jim Morrison, keyboardist Ray Manzarek, guitarist Robby Krieger and drummer John Densmore honed their skills, both musical and theatrical.

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An often absent crowd gave the quartet freedom to experiment, emboldening them to introduce daring original compositions alongside covers of early rock and R&B standards by Chuck Berry, Muddy Waters, and Big Joe Williams. Unlike their bar band contemporaries, the Doors brought jazz sensibilities to their set, exploding each song and exploring individual sections with lengthy instrumental solos and improvisational lyrical passages. Though they would ultimately find fame and fortune a few doors down at the Whisky a Go Go, where they served as the house band later that summer, the Doors truly came of age at the London Fog.

A tape from this thrilling period, recorded by the band’s friend Nettie Peña in May 1966, was recently rediscovered and is now available as part of a limited-edition box set, London Fog 1966. To date, it’s the earliest known document of the Doors in action. Rounding out the collection is an assortment of facsimile memorabilia, including a set of 8×10 photos, handwritten setlist, and even a London Fog coaster. The effect is deeply evocative, offering a vivid time-capsule of the ’60s Hollywood underground scene.

On the eve of the 50th anniversary of the Doors landmark self-titled debut, Krieger, 70, tells PEOPLE about those exciting early days before the band became stars — and before Morrison became immortal.

Image zoom Edmund Teske/Michael Ochs Archives/Getty

What was it like hearing these tapes for the first time?

I thought it was pretty cool, man. I was amazed at the quality of the sound. We were a little rough around the edges, but I thought we sounded pretty good.

What comes to mind when you look back on that era?

Just how green we were, you know? Especially me, I’d only been playing electric guitar for maybe a year at the time. Less than that, even. The fact that we had such an odd set up — with Ray playing the bass keyboard and the organ and no other guitar player, just the three of us playing instruments — it really formed my style. I think if I’d just been playing with some other band, a normal rock band, it would have turned out totally different.

How did you first get the job at the London Fog?

That’s a good question! Basically, we just used to go around and hound all the club owners and ask them if they’d hire us. We hit all of the spots on the Strip, and the London Fog had just opened up. I think we were the first ones to play there. It was a small place, mainly a bar, but it did have a stage. By this time we’d gone through about 20 or 30 different clubs and been rejected. We learned the ropes and said, ‘Listen, man, we can fill this place up!’ And we did. The first night we got all of our friends to come from UCLA and everywhere and it was packed. So the guy hired us.

Of course, the next night nobody came. [laughs] It was two people. But it slowly built up. On the Strip there’s a lot of foot traffic. They’d leave the door open so people could hear what was going on inside. I don’t think there was a door fee. If you came in you had to buy a couple of drinks.

What was the audience’s reaction when you’d switch from Chuck Berry covers to originals like “The End.”

It depended on who was there. It seemed like most of the people didn’t really care about dancing too much, they were just gawkers. If they wanted to dance they would go somewhere like the Whisky where they had a real dance floor and go-go girls. Although we did have a go-go girl, Rhonda Lane.

It must have been hard for her to go-go dance to “Strange Days”…

We had that experience a few times, where dancing girls would complain about our music. I remember this one gig we played, this guy had booked this theater. We were one of the bands, and he had this exotic kind of dancer. So we started to play “The End,” and she was getting more pissed off as it went along. And at the end she went, “Never play that song again when I’m dancing!” [laughs]

The box set has early versions of “Strange Days” and “You Make Me Real.” Why were neither of those songs included on your debut album?

It wasn’t that we thought they weren’t good enough for the first album, but we had to pick and choose. A lot of good ones didn’t make it, like “Moonlight Drive.” That was the first song we ever worked out and that didn’t make it on the first album. When we went to record the first album, the first one we did was “Moonlight Drive.” But it just sounded too mysterious and kind of dark. So we rearranged it for the second album and made it a little more wild.

Had you started writing when you were playing at the London Fog?

Oh yeah. We had “Light My Fire” worked up, and some other ones — maybe “You’re Lost Little Girl” and “Love Me Two Times.” But unfortunately, [Peña] had two boxes of tape and only found one. I hope she finds the other one, because “Light My Fire” was a totally different arrangement and it would be interesting to hear that.

Those were the days when Jim would turn his back to the audience. Was he shy?

When we first started we were so used to just rehearsing, and we’d set up in a circle so we could see each other and see what the other guys were doing. Jim just got used to it. It took him a while before he realized he was supposed to turn around and face the audience. [laughs]

It must have been impressive watching his confidence start to grow.

Oh yeah, for sure, man. [The London Fog] is really where it happened. He really came out of his shell during that period. He was pretty laid back as a performer in the early days. He’d never really sung before. It was new to all of us, except for Ray. Ray had been in bands with his brothers. At the Fog, Ray sang a lot of the songs, and Jim would just play tambourine and stuff.

When did you know this group was something special?

I think I knew from the first time I played with them. When we first played “Moonlight Drive,” as a matter of fact. It was like, “Wow, this is different.” Because I’d played with other guys. I was in a band called the Clouds, and [also] the Psychedelic Rangers. But this was different. The thing was, Jim had these songs — he had six or eight of them by that time. We knew they were great lyrics. But it wasn’t until we started playing the Whisky that we started blowing these big groups off the stage. That’s when we knew we had something going. We played with Buffalo Springfield, the Turtles, Van Morrison and Them. That was incredible, I think that was our second week. Our first week there was a group from Mexico called the Locos, so we played second fiddle to them.

How did your time at the Fog come to an end?

I think what happened was that he wasn’t making enough money and he closed the place down. He couldn’t make the rent. And of course he blamed us. I don’t remember if we got fired first or if he closed down.

When you listen to these tapes now, what do they remind you about Jim?

I just hear his voice. It’s so unformed at that point. He hadn’t really found his voice yet, which didn’t happen until the Whisky, pretty much. It’s pretty amazing how unformed his voice was, at least to my ear.

What does it remind you of Ray?

I just remember how he held the whole thing together, as far as keeping the tempo and everything. Every song was always the perfect tempo. That wasn’t really John, John was more playing off Jim, I think. He didn’t have to keep time because Ray did such a good job. John played some pretty unusual drum parts if you really listen to them. It’s very subtle. Like “Break on Through,” that bossa nova beat that I don’t think anybody would have tried on a rock and roll song at that time. And “Whiskey Bar” [“Alabama Song”] with that total German up and down beat. And “When The Music’s Over” — if you listen to what he does on that, it’s pretty amazing. “Light My Fire” during the solos, especially during Ray’s solo when he doubles up at one point, and then it goes back to regular, and then he hits the off-beats at the end.

Next month is the 50th anniversary of the Doors debut. Are there any other projects or celebrations in the works?

There’s a whole bunch of stuff — Jan. 4, John and I are gonna go down to Venice Beach to where it all started and they’re going to have a shindig down there announcing that this is “The Year of the Doors” in Los Angeles. And then hopefully we’re going to put out a film of Ray’s tribute concert we had in L.A., if we can get that footage together. I think we have some pretty good stuff.

I’ve read Ray’s book, Light My Fire, and John’s book, Riders on the Storm — do you have any plans for a memoir?