Great Basin

What was once a vast ocean across the world of Sundry has become now The Great Basin.

Appearance
The basin covers a gargantuan span of land hundreds to thousands of kilometers across. As it is largely below sea level, and dotted across its expanse with geothermal vents, hot air tends to stagnate here, making traveling along its length arduous and difficult for those who need to breathe.

The deeper down the basin one travels, the stranger the landscape grows: small ridges and caves turn into entire mountain ranges and gorges many times deeper than the eye can see. At its deepest points, the mountains turn to volcanoes and the gorges to geothermal vents that produce most of the stagnant heat of the basin.

Phenomena
Along with the size, rough landscape, and omnipresent heat and humidity that make traversing the Great Basin difficult already, one may witness strange sights the longer they stay within the basin, that tend to grow stranger the longer one stays down there. Sights seen include:
 * Bones organized in unnatural structures, some of which are in standing or seemingly active poses
 * The sun traveling across the sky in a swirling, inconsistent loop instead of a steady line
 * The moon becoming totally invisible without warning and reappearing hours later
 * Mountain ranges that seem to shrink as you approach them, until they are barely more than small ridges one can step over without any thought
 * Massive petrified shipwrecks that have turned entirely to stone, some of which float slightly off the ground
 * Large bronze portholes in the ground that are locked and cannot be opened, but that sound hollow on the other side
 * Standing doorways in the middle of vast, open expanses; those whom have opened the doors walk through and do not return
 * Titanic bony hands rising out of the rifts and crevasses and flailing about before dropping back into them
 * Giant, pristine ivory walls extending dozens of feet into the sky
 * Large, shattered stone tablets with the following inscribed (some of these partial):
 * "NIHIL PROHIBET IN SC-"
 * "SUNT AD F-"
 * "-EO ET NON IN MANUS NO-"
 * "NOLI RESPICERE POST TE-"