One of the two environment designs for the artstation challenge:
"Candletown is one of the few cities of the underworld.
The town is ancient and people also know it as “The last beacon” for it is the only light in the darkest depths of the underworld. The town is lit and powered with great candles made with a wax-like sap named Linfa secreted by trees that grow from the ceiling of a huge cave system. The people of Candletown created containers that gather and stir the Linfa to prevent it from solidifying.
The containers are powered and heated by candles (the heat helps with preventing hardening).
The humid climate of the cave also helps with keeping the property of the Linfa intact.
The Linfa has also a great variety of uses. After being slightly cooled it can be manipulated like clay and dried into different kinds of containers and decorations. At its rawest it can be cast like melted metal, this process is used to produce the candles and other utensils.
Once the cast hardens the Linfa will become incredibly sturdy although heat will slowly melt it back to its raw state.
Being the climate of the underworld really cold and damp any object made of Linfa can be easily preserved and it ended up being the main building and crafting material for the townsfolk.
The machinery to harvest and process Linfa is of unknown origin and the townsfolk of Candletown lost the knowledge of their ancestors after the coming of the first occurrences of the “Great Dark”
they can only maintain the conditions of machinery as best as they can and operate minor repairs"