This planet has seen many strange occurrences, over its millennia. Alien visitors. Intelligent stones. Life without a body in the form of spirits. Old rituals by humans and by dragons, made into something of real power by inertia alone.
Here is a circle of standing stones, standing tall and proud and each carved with moss-covered and worn artwork. Stone circles serve as gateways to Elsewhere, sometimes. There's a sense of tension in the air, as if something has been built up too high, wound too tight, and is about to snap. The spirits pay close attention, here and now, curiosity and anxiety as to what might happen next.
A storm is what tears open the veil. Lightning strikes, and for a very brief time the stones glow a pale blue, opening a conduit to elsewhere and reaching out near-randomly for people to provide passage to. It's not a proper working, but a broken one. Anyone will do, really. Particularly those who are lost or wandering right now.