When I was in Argentina, in February, I visited a tourist attraction called "El Puente Del Inca". At the time I had no idea what the history of this unusual location was, so I did a bit of investigating. Turns out this place was visited by, none other than, Charles Darwin. Scientists speculate that interaction of extreme elements like ice and hot springs was involved in the origin of the formation. They suppose that in ancient times ice covered the river and acted as support for avalanches of snow, dust and rocks. So the dust over the ice over the river would have served as a path for the sulfurous water and petrified the surface, so when the snow melted, the bridge remained by itself.
In the early twentieth century there was a big Thermal Resort and Spa that used the hot springs to cure some illnesses. There was a train station that still remains, and tourists arrived by train to the resort. This was one of the last Argentine stations of the Trans Andine Railway before the train continued into Chile, traveling through a long tunnel under the Andes.
The Puente Del Inca Legend:
Many years prior to the arrival of the Spaniards, a great Inca chief had a son suffering from paralysis. After trying all sorts of cures, with no result, the Chief heard that in the south lands there was a place where healing waters could put an end to his son's disgrace. Without delay, he prepared a group of his best warriors and made his way to the high peaks. When he arrived he observed, in amazement, the famous waters that came out of the earth, but before them lay a torrential river that denied them access. His warriors, to make their chief's dream a reality, did not hesitate to embrace one another, and forming a human bridge they reached the other side. The Incan chief walked over their backs with his son in his arms and reached the thermal source where he found the cure he sought. When he looked back to thank his warriors, according to the legend, they had been turned to stone, creating the famous "Puente del Inca".
So now we know what the "Puente Del Inca" is all about.
