Valera is a world unlike any other world.

  A titan drifted very slowly and ponderously through the void. Its horizon curved so subtly that even the tallest mountains vanished into the haze before they could cast a shadow. Its days were not measured in hours, but in years. One full rotation took thousands of Earth days and it finishes orbits its giant red mother star once every 6770 days. It was a world of extremes, a world of fire and ice.

  On one side, the sun never set. It loomed in the sky like a molten god, unblinking, unrelenting. The land beneath it blistered and cracked, scorched by over multiple Earth years of continuous daylight. Temperatures soared to four hundred degrees Celsius or even higher. Rocks melted and metals softened. The air shimmered with heat mirages, and the ground itself glowed faintly in places, not from lava, but from the sheer intensity of the mother star radiation.

  On the other side of the planet, the darkness reigned. A cold so deep it silenced everything, even the fastest wind vanished. The nightface of Valera was a frozen tomb, locked in shadow for years of planetary time. Temperatures plunged to minus one hundred degrees and sometimes even lower. The atmosphere thickened and slowed, and condensed into seemingly eternal frost and snow. The landscape is just plain white and unbroken even by the cloud or moon.

  Between these two hells lay a narrow ribbon of mercy, a twilight zone where the sun hovered eternally near the horizon. Here, and only here, could life survive. However, this fragile band of habitability was not still. It moved. The twilight belt crept westward, a slow and steady march driven by the planet’s rotation. To remain within it, one had to move relentlessly westward at an unforgiving pace of at least fifty-four kilometers an hour. Anyone who tries to move any slower will fall into the frozen void or scorching hell.

  This story has been taken without authorization. Report any sightings.

  However, there are plenty of living creatures that thrive in this torture. Some move periodically to stay in the small paradise, others adapt to appear when the twilight zone passes and hibernate deep in the ground when it’s a living hell. Humanity here adapts not by building stationary cities, but machines called the Crawlers.

  Some are colossal, mobile habitats that span dozens of kilometers, while others can be as small as it can only fit 1 full family. They crawled across the surface of Valera like armored beasts. Their segmented bodies undulate over plains, climb mountains, and pass over vast valleys. Some were designed sleek and narrow to reach high movement speed, while others were squat and broad, prioritizing redundancy and resilience.

  At their hearts, a giant burning chamber, burning multiple types of fuel that can be found. Supplementary energy came from solar collectors angled toward the horizon, and geothermal taps drilled into the crust during brief stops. Wind turbines lined their flanks, harvesting the jet streams that screamed along the terminator.

  “But dad, why does it seem very crowded?”,”Well kid, . . . the belt itself was a living thing. Only three degrees wide, it was not uniform. Its path wavered with the seasons, dragged north and south by Valera’s steep axial tilt. Over the course of the long year, the twilight zone traced a slow sine wave across the planet’s surface. Cities that remained near the equator enjoyed relative stability, needing only to adjust their westward pace. But those who lives om higher latitudes had to climb and descend thousands of kilometers annually to remain within the never stop moving habitable zone.

  “And then dad?”, “Well we have arrived to our destination kid, i’ll tell more later on”, A pair of father and son has just arrived to their destination, a gigantic crawlers spanning 20 kilometers wide and 30 kilometers long with a fully functioning society living in it.