Quota, weather and ranger contact, etched onto a stone at the trailhead
The Inca Trail to Machu Picchu admits a fixed 500 hikers a day, a quota set to protect the stones the trail leads to. QR codes on stone markers at Kilometer 82, and at the alternative Salkantay and Lares trailheads, now show the day's remaining permits, current weather in Spanish, English, and Quechua, the nearest ranger's radio frequency, and the river-crossing status on the four-day route. A 600-year-old footpath gets an admissions desk that fits on a rock.