The 'Breath of The World'

The Breath of The World was the name given to geothermal energy when it was first discovered by the Nisseans. The Nisseans became very adept at harnessing geothermal energy as their civilization continued to dig deeper and more elaborate structures. They would use it to give light to homes, heat structures and even to push running water through large water circulation systems that rely on heat transfer. Before their disappearance, the Nisseans even researched its potential for weaponry, though it is unknown why official research stopped.

The Breath of The World is even thought to power a complex device that accurately maps the movement of the inner planes of the cosmos. Similar to how the average orrery charts the planetary bodies beyond our own, the 'Breath of The World' may power an orrery that charts the very planes of existence in relation to our own. If such a fact turned out to be true, the possibilities of this geothermal energy could be endless!

Utility

The Breath of The World is used to heat buildings, power heat activated lights and circulate plumbing. Having been discovered completely by accident, there is no regulation on its use and attempts to create weaponry that would manipulate the heat energy has been attempted but, to date, none have been successful to public knowledge.

Manufacturing

The systems are almost completely crafted from meteoric iron and use the heat of the planet to transfer air and water through specially constructed channels at a very fast rate. As the air rises, it is channeled into smaller pathways that eventually branch off to homes and other structures. The water (which is now steam) is condensed and collected into a network of pipes that are artificially heated to push the water down the final stretch to its destination. The final section of these water channels is typically made of stone to cool the water before it comes from its faucet or spigot.

Inventor(s)

It is currently unknown who invented the systems used to harness the geothermal energy that is the 'Breath of The World'. We know only that its discovery is credited to the Nisseans in all of our texts.

Access & Availability

In their prime, these systems would function swimmingly, with constant upkeep being performed around the clock to keep families warm against the harshness of winter and bring potable water to them from the depths of the planet.
The Breath of The World is still commonly used by folks every day but to varying degrees of success. Modern-day peoples devote their studies to these ancient systems in the hopes of understanding how they were built, how they can be repaired and how they can be replicated and improved upon.
As it currently stands, most major cities have a hard time keeping the systems up and running due to the fact that there are so few who understand how the systems work and less still who know how to repair them.

Complexity

None still exist who know how to create new geothermal systems, as the ways were lost along with the Nisseans , but the fact that such technology still exists and functions after several thousand years (to varying degrees of success) is a credit to the Nisseans genius and hubris.

Discovery

Originally, 'The Breath of The World' was simply used to describe the heat one felt when they were too deep underground, but as time went on, the name was eventually used for the complex geothermal heat transfer system that the Nisseans invented and constructed in all of their major cities several thousand years before recorded history.
As the Nisseans continued to craft their homes deeper and deeper underground, it became apparent that heat would be a constant factor. What originally started out as a system that would vent heat to protect workers became a convenient and popular heat transfer system that could be used to heat homes and power glow stone lamps on the streets. Using the heat, water could also be transferred over great distances which brought the invention of rudimentary plumbing to these proto-peoples.