The area surrounding Mendoza, Argentina is of great historical importance, having been used as an important pass connecting the east and west parts of the South American continent. There is a natural bridge called Puente del Inca, not far from Mendoza (towards the Andes) over the Río Mendoza, that used to have a hot spring. It is hypothesized that the bridge itself was formed by the accumulation of sediment over ice, such that the sediment petrified, and when the ice melted, it left the orange, yellow and ochre-colored bridge behind. The bridge was given its name due to the presence of the Inca people in this area, and the belief that they would have visited the springs for the curative qualities of the water.
The bridge itself sits at about 9,000 feet, and is closed to the public, due to some instability in the structure, but it is still very photogenic. The area surrounding the bridge is spectacular, and includes views of several major peaks surrounding Aconcagua, including Tupungato, which tops out at 6,650 meters. Also nearby is the Cementerio de los Andinistas, built in homage to mountain climbers, both those who perished in the Andes, and those who had tremendous respect for the mountains.
Crossings in this area are tricky in winter months, due to blustery weather at the pass. Keep a close eye on weather conditions, and plan your trip for days with stable weather.