In time, the dedicated Spelunker will grow to instinctively recognize unreal architecture, senses picking up the minutiae that others miss. Wind coming from impossible directions; shadows cast at awkward angles; a dearth of wildlife; a strange doppler effect to sound, as though distance between source and listener stretched like taffy. Details and nothing more, but the details separate lost wanderers from professionals and the details are where the devils lie.

“Is this the building?” asked Dalvey, who knew the answer before the question left his lips. The subject of conversation was a nondescript, beat-up apartment block like the ones to the left and right, the brightness of the afternoon sun reflecting off windows and rendering the interior occluded.

“Check your map, Andy,” said Benjamin, midday glare reflected on beads of sweat on his forehead, migrating down the furrows of middle age and merging into rivulets that got lost in two days of stubble. Dalvey didn’t have to, the building wouldn’t be there, not on Google, not on print, and perhaps only in the memories of half of the neighbourhood. This was part of the ritual of their meetings. After thirty years, greetings became meaningless signals, part of the syncing algorithm old friends partook of, fresh information parsed and filed and forgotten.

Over the years, the competing gravities of distance and social circles had tugged at their friendship. Dalvey’s multiple stints on production lines being one of many Andy’s hardened his surname around him like a carapace, till there was nothing left but a uniform and a name tag. Benjamin got out, reached escape velocity out of small town backwoods, powered by the rocket of his brain, made enough money before the first crash, enough to retire once, go back into consulting from his home and retire again just around the second crash, coasting the waves of finance like some kind of unsinkable dinghy bobbing to the surface every time.

If not for one common hobby, Dalvey and Benjamin would have drifted apart, perhaps only with Facebook birthday notifications and yearbooks to remind them of shared guilt. They looked up at the abandoned building, knowing that the main door would have the accoutrements of modern architecture; burglar alarms and camera systems, yellowing like teeth under the elements; double doors with streaky glass; gaping mailboxes belching forth fliers and advertisements. And yet, were the two men to have compared what they saw to the details, the discrepancies would have added up. The colour of the doors, for instance, dark blue to one and green to another. Or perhaps the number of floors to the apartment building, or which windows were open or a dozen little things. For these buildings never looked the same to any two people.

“Come on,” said Benjamin, hoisting his gear up onto his shoulder. “We haven’t got all day.”

Unreal buildings are often mislabelled as haunted houses and the like. Their elusive nature makes them difficult to study, for there is no guarantee that the building will be in the same place the next day. Speculation on their existence is confined to forums like ours. While the exterior presents discrepancies to casual observers, interiors are far worse, physics and time seem malleable, with impossible room designs and even time itself becoming untrustworthy.

“Where to?” asked Dalvey. The ground floor was mercifully deserted, the building superintendent’s office empty. The temperature inside was chill; papers blew along the floor, dust swirling in tight spirals. Benjamin gestured to the shut door, the paper streamers on the vents that lay still. No way for the wind to get in. Then he pointed up.

“To the top,” he said, making towards the elevator.

The maintenance certificate in the elevator was blank and yellowing, the buttons arranged in a grid of at least thirty, some of the plastic was cracked, spiderwebbed fractures reminding Dalvey of crushed be...