[morbidious]

"There is a great stupa which constantly glows.", is that metaphorical or real?

[moogleii]

Maybe it was capped in gold or something

[GolfPopper]

Or luminous gems: https://en.wikipedia.org/wiki/Luminous_gemstones#Mineralogic...

(I'm not remotely an expert, but it seems like at least a possibility for an explanation, and it's a interesting and seemingly little-known class of phenomena.)