But this lower Uspallata Pass, which has always been the principal means of land communication with Argentina, was destined to become famous in another way, because (as already mentioned in the chapter on Argentina), it was the place chosen as the most suitable for the route of the Chilean-Argentine transcontinental railroad, connection between the eastern and western sections of which was established in April, 1910, by completion of a tunnel through the mountain two miles long and half a mile beneath the Cumbre—a work of the utmost importance, for, aside from the matter of comfort and saving of time, it has made it possible to go from one country to the other by the land route in winter, when the pass above is covered with drifts and the deadly winds and snowstorms are so likely to whirl down on the traveler at any moment that few except the hardy mail-carriers ever dared attempt it.
In this neighborhood the mountains attain their greatest altitude. A few miles to the north and visible a little distance from the Cumbre is the “Monarch of the Andes,” Aconcagua, which, according to the record at the Harvard University Observatory in Arequipa (Peru), is 24,760 feet (more than four miles and a half) high—the highest in the world, it is now regarded, next to Mt. Everest in the Himalayas. In his interesting story of the ascent of Aconcagua, Sir Martin Conway, one of the very few who ever succeeded in accomplishing it, gives a good idea of the region, viewed from a point near the lesser of the two summits. “At last I heard a shout and looked up and saw Maquignaz a yard or two above my head,” he says,
“Standing on the crest of the bed of snow that crowned the _arête_. In a moment I was beside him and Argentina lay at our feet. The southern snow face, delusively precipitous though actually as steep as snow can lie, dropped in a single fall to the glacier two miles below. To the right and left for over a mile there stretched, like the fine edge of an incurved blade, the sharp snow _arête_ that reaches from the slightly lower southern summit to the northern. It forms the top edge of the great snow slope down which we were looking, and is only visible from the Horcones valley side as a delicate silver crest, edging the rocks. At many points it overhung in big cornices, like frozen waves about to break. The day had thus far been fine, but clouds were now gathering in the east. Fearful lest the view might soon be blotted out, I took a few photographs before moving on. The view abroad from this point differed little from that which we finally obtained. To the south was Tupungato (22,408 feet), a majestic pile of snow, over which even more majestic clouds were presently to mount aloft. To the north was the still grander Mercedario (22,315 feet), beheld around the flank of the final rocks. In the west were the hills, dropping lower and lower to the Chilean shore, and then the purple ocean. To the northeast, like another ocean, lay the flat surface of the Argentine pampas. Elsewhere the Cordillera, in long parallel ridges running roughly north and south, stretched its great length along, crowding together into an inextricable tangle the distant peaks, partly hidden by the near summits, which alone interrupted the completeness of the panorama.”
