I’m rather inspired that there’s a gaming history involving ley lines. A way for multiple fluxuations in the magical powers running through the earth that focus nacient energies. Flows of energy might interact in waves, constructive and destructive.
Consider the amount of minerals buried in the viens below Galentaspar. Not only dwarves noticed it — but orcs, drow, giants and dragons noticed it. Some grew to understand the warp and weave created by the mineral veins below what is now the gravel pit. Some areas are positive, others the opposite.
What areas summoned your characters? What areas repel them?