I've always like the idea of light pipes: https://worldbuilding.stackexchange.com/questions/130769/can-fiber-optic-cables-be-used-to-pipe-sunlight-into-an-unde

I've always like the idea of light pipes: https://worldbuilding.stackexchange.com/questions/130769/can-fiber-optic-cables-be-used-to-pipe-sunlight-into-an-underground-bunker-for-g https://worldbuilding.stackexchange.com/questions/130769/can... https://en.wikipedia.org/wiki/Light_tube https://en.wikipedia.org/wiki/Light_tube