Another painting concept for this rpg thing I've been working on. Kaza Rhun is a large, tube-shaped city set back into a granite wall in a vast underground cavern, beneath a "gasp" - which is an airhole up to the surface. This painting is at noon, so the sunlight is jutting directly down to the water below - the only time of day the cavern sees sunlight. A gasp is useful for a number of reasons - mainly because of the surface run off and rain bring down lots of water and nutrients from the soil, and little creatures too - which makes the cavern below and its lake very fertile. The lake grows bioluminescent mushrooms, too.
This was done a while back, so I forget exactly how long it took. Much frustration with OC's lack of easy textures, hence... very cheap and horrible textures in Paintshop Pro (which I hate, but it's all I have). Came out okay, considering.
(Open Canvas, some time more than an hour, wacom tablet)