Chasms

Chasms are similar to our Earth’s canyons: dramatic gouges in the landscape often flanked by sheer cliffs. They can range from a few hundred feet across to hundreds of miles, though most are under 10 miles wide. The chasms cut across all terrain, including the oceans. However, the chasms are much shallower below sea level. The ocean levels were altered by the formation of the chasms, but not enough to substantially shrink them.

When the chasms formed, the ocean levels dropped. All landmasses now have a cliffs along their coasts, between 100 and 500 feet in height. The chasms continue into the oceans and if one were brave (or foolish) enough to look, the oceans continue into the chasms as well. Their floors tend to mimic the elevation and composure of the of the regular landmasses above (rocky, sandy, hilly, etc.). Any villages or towns near the coastal cliffs may see or hear the tides, depending on the depth of their local chasm.

However, explorers have found a curious feature of the chasms. Not far past the coast, the chasms floors suddenly drop. The seawater is thrown over the edge in a constant waterfall down into the depths. This constant stream of water is what is thought to create the Mist that shrouds most chasms. The people of the world do not know where the water goes, or how the oceans don’t simply drain away. There is, however, a closed loop of water. The seawater the flows into the chasms travels in great underground rivers, until it is released into the ocean once again by springs/vents in the deep ocean floor. This water is now rich with minerals, and helps maintain the biodiversity of the oceans.

The chasms have not been a feature of the world since its beginning. The chasms formed during a cataclysm near the start of human history. Humans had built a civilization: language, trade, animal domestication. The cataclysm hit, tearing the Earth’s crust apart, creating the chasms and islands. Mankind and creatures were separated from one another, and almost all civil progress was lost.

The chasms are very, very deep: often miles deep around larger islands. Subterranean creatures do live in the depths, but mankind has not penetrated the mists that have settled within the chasms. People live on the edges of the chasms, even on cliffsides. Since the chasms were formed after the major formation of the planet, the chasms often have ores and other treasures of earth exposed.

Human Modifications
The chasms obviously make transport very difficult for anyone that does not have access to a pegasus to fly them across. At some point, a brave and probably somewhat reckless soul took a look at a chasm that was only a couple hundred feet wide and said "I could build a bridge over that."

While constructions of stone or wood are rare, many small islands are linked to their neighbors by rope bridges or zip lines. There are even rumors of some places with "chasm ferries," though no one is ever quite sure where they are or how they would work. (X to doubt.)