Mariunhus was a vault-spire on Muunilinst, one of the many small cities located out at sea, the foundations of which were built around the cones of active underwater smoker volcanoes.

These volcanoes were known for spewing out superheated gases containing precious and pure metals. Entire mountains of gold, platinum and other metals had been formed over the eons, eventually covered by mollusks, bioluminescent ferns and tubeworms.

Thus, the wealth and currencies of offworlders were essentially guaranteed by mountains covered in sea life.