With a recently completed new tunnel, the route up over the Andes from Mendoza, Argentina to Santiago, Chile is a smooth seven-hour bus ride with great views. I say it ranks right up there with the Cabot Trail and The Columbia Icefields highway, tops in the North America, If not the world. The constantly changing views of the colorful mountains meant no napping on the bus.
Folks in Mendoza enjoy cross-boarding shopping because they are closer to Santiago than to the metropolises of Argentina. That said, the descent from the highest point on the highway, at Mt. Aconcagua (tallest mountain outside the Himalayas) viewpoint down to the plains of Chile and to Santiago takes so many tight switchbacks in a series that it is undoubtedly nauseating for some people.
Aconcagua is arguably the highest non-technical mountain in the world, since the northern route does not absolutely require ropes, axes, and pins. Although the effects of altitude are severe (atmospheric pressure is 40% of sea-level at the summit). Even if the normal climb is technically easy, multiple casualties occur every year on this mountain because many climbers underestimate the objective risks of the elevation and of cold weather, which is the real challenge on this mountain. I have a few Alpine Club pals who have attempted the summit but not achieved it - one of them tried twice. Hard core chick, that Terri.
Paso Internacional Los Libertadores is an easy border crossing, with both the Argentine and the Chilean immigration posts located inside the same building, making it surprisingly efficient. All I had to do was eat/toss the apple I’d brought along from Argentina and we were back on the bus in no time.