Montgolfier Post

France, 1785. Carry the royal post by hot-air balloon over a hand-tinted copperplate countryside. The wind blows differently at every height: burn to rise into a layer that carries you toward the vermilion meadow, vent to sink onto it, drop ballast for a last step upward, and hand the sealed letter down. Twenty authored routes across five post roads, thermals, downdrafts, the mistral, narrow alpine rings, stamps and a postal-accuracy leaderboard.