Abra El Acay - Acay Pass (Argentina)
The sign indicates an elevation of 4,895 meters - 16,059 feet (but according to Wikipedia, its altitude measured by GPS is 5,061 m). Located on Route 40, this is one of the highest motorable pass in South America (Peru might have some higher passes).
Despite all the signs and local people telling me that it was a very difficult road, I had no problem at all with my rented Volkswagen Gol, but the season was exceptionally dry this year and the river level was lower than usual.
You can attempt to cross this pass with a pasenger car only if the weather is very dry (no rain in the past several days) and if there is no chance of storm. If you get stuck or break down, it might take days to get you (and the car) back to civilization! So be prepared for the worst case.