How to light megastructures in Minecraft without torch orglowstone spam?

Solution 1:

This is due to the way lighting works in Minecraft. Any block emitting light that is not marked as a sky light has brightness at most 15 and falls off with each block of distance. Daylight / sky light is based on whether there is an unobstructed path of light to the sky (not including transparent blocks such as glass but including certain light-filtering blocks, see the wiki page for details). In vanilla there is no way around lighting huge caverns except for using daylight. With a modpack there may be "floodlights" that simulate the effect of daylight, or produce "beams" of full brightness light-emitting blocks.