Alpine is a Tier I promotion for recon units in Civilization VI.
Effects
Civilopedia entry
While some early tribes were adept at trudging across the hills and mountains of Europe and Asia (in fact, many primitives had strong superstitions concerning the "high places" and tended to avoid these), in general it wasn't until the Renaissance that military units were formed in Switzerland, Austria, Italy, Germany, and even India with the skills to operate in hilly terrain. Since warfare began, holding the high ground has been important for victory; these alpine formations – usually small – not only scouted the lay of the land but looked to insure it was held by their side.