In his 1940 short story The Lotus Engine, Golden Age science fiction great Raymond Z. Gallun describes an expedition searching for antiquities on a distant world: Io, a moon of Jupiter.

They stumble across an amazing artifact - the boiler of the sun plant:

The thousands of reflecting mirrors of that solar motor, mounted on their slanted, circular frame, were collecting the feeble rays of the tiny, far-distant sun, and concentrating them on the blackened boiler at the center of the frame. The boiler was made like a squatting image of one of those last natives. It had a great beard, carved out of iron, ruby eyes, long goblin nose and ears, and a strange, mocking, secret grin on its lips - a grin that was sinister in itself...

('The Lotus-Engine' by Raymond Z. Gallun)

So, we'd polished the reflecting mirrors of the sun-plant. We'd patched and repairs the leaks and dents in the boiler, turbine, and other parts. We'd filled the dried-out boiler from our ship's precious supply of water. We'd applied oil liberally, where necessary. Just at evening we'd got that huge, tip-tilted reflector frame turned around on its pivot, so it would face the sun at dawn.

And now, coming back from our ship in the early afternoon, we were flabbergasted to see that the world-old engine already in operation, its throttle evidently opened by an automatic device!

...As the hours went by, a gear-system became active on its pivot and gimbals, keeping the great, iron ring and its mirrors faced toward the sun, so as to collect all the heat possible for the boiler.

Incredibly, after all that time, the ancient solar power plant began collecting the energy from the local sun. But where did the power go? Seemingly, deep underground.

The treasure-hunters begin to experience visions of what the moon was like when it was inhabited; they heard weird alien music.

Well, right then Russ Abfall began to swear at me. "You loony nut... Don't you realize that this is all a fake - a mental phantasmagoria of some kind? It's one of the enigmas of a dying race... That damned sun-plant - and whatever its underground wires are attached to! Visions! Hallucinations! Somehow that hidden apparatus causes them!"

...Anything was possible in my imaginary environment. I could imagine myself Caesar or Alexander the Great, if I wanted to, and my fancies would seem perfectly real around me... I don't know much about how Caesar's Roman Legions were organized, and their equipment is hazy to me - but still I could construct for myself a vivid living picture...

In moments of panic, I tried to break the spell of dreams, and fight my way back to truth. It was then that I discovered that I was in a trap...

"Hey, Milt!" someone was calling, in tones as faint as if they originated a thousand miles away... "We've got to snap out of this!"

...It was Russ, of course... I struggled furiously, using all the will I could muster. And the dream fought back... And around me, maintained only by force of will, was grim fact!

I was in a deep vertical shaft - a sort of well. Jagged walls of stone were around me... I was sick and worn out... My hands and arms were so emaciated they fairly rattled inside my space armor...

"You know what reverie, or daydreaming is, Milt?" [Russ} asked... The phenomenon that has tricked us, is just a kind of reverie, enormously improved by artificial means...

"We must be dealing with a form of radiation here, Milt. Something that beats on the nerve and brain cells...

But suddenly I wanted things real, myself. The real Earth and not these empty phantoms...

We found our way to the sun machine, a quarter-mile distant.

The thing's flywheel still spun steadily... Then Russ and I raised our pistols. As twin dynamium capsules struck the machine, there was a thin, distant-sounding, though mighty explosion.

With the power cut off, it's back to reality!