In H. P. Lovecraft's late (and surprisingly anticolonialist) story "In the Walls of Eryx," coauthored with Kenneth Stirling, two prospectors working in the Venusian jungle get successively trapped in a perfectly transparent maze. Neither one of them makes it out alive, despite each of them dying very near the exit (which they cannot see).
The story seems straightforward to me, but I have read several other claims that there must have been a secret doors--moving panels that had closed the men in. I can't see any indication that this might be the case (although I suppose it cannot be ruled out from the story). So am I missing something that does suggest that there are secret doors In the Walls of Eryx?