Frostways
You’ll find these high-fantasy magical highways anywhere that has both a high mana level, and a climate that averages below freezing for half the year. To create a Frostway: first, make a road between Point A and Point B. Over it, construct a lattice of stone or brick arches spaced regularly so that they cover (with large gaps, of course) the entire road. Then, cover the road surface itself with ice, and the lattice with either packed snow or ice blocks or whatever other form of solid water local custom favors. Then cast a particular spell.