Puente del Inca is a natural arch spanning the Las Cuevas River at 2,744 metres altitude in the high Andes, about 165 kilometres from Mendoza along the road to Chile. The arch is the product of mineral-rich hot springs that have encrusted glacial debris into a solid, brightly coloured structure — yellows, oranges, and reds from sulphur deposits contrasting with the grey rock walls of the valley. It is genuinely striking and worth the drive even on a day trip.
The arch itself is small enough to walk under, though access is sometimes restricted. Around it cluster the ruins of a former spa resort, abandoned since the Transandine Railway that served it was destroyed mid-20th century. The ruined baths continue to be slowly encrusted by the spring water, adding to the surreal character of the site.
The drive from Mendoza through the Uspallata Valley to reach Puente del Inca passes through some of the most dramatic Andean scenery accessible by paved road in Argentina. Many people combine a visit with a stop at Aconcagua Provincial Park, which begins not far before. The road continues over the Paso Los Libertadores border crossing into Chile.