"How far? Ye’ll know ye’ve found Malver’s Way when ye sees the Arch."
Gnomes, fascinated with magic, tried to find a way to safely access it, and instead wound up addicted in the deadliest way.
Thaumatechnology - in a world where straight magic has an unnerving tendency to get the user killed, either by magical catastrophe or by being lynched by an upset mob, this is a much safer form of magical use… Even if it does occasionally explode.
You receive a vision of a rooftop "somewhere close by", where a rare moss grows; in the vision, you know the moss is suitable for greatly enhancing the effects of certain types of potions. Now go and find that rooftop. Don't fall off. (Of course, rooftop runners *will* be taken for miscreants by the local City Watch....)