Natural Wonders of the World [antikvár]

Aar Gorge • Switzerland • Map: page 17, D-4 A glacier-fed river has sculpted this deep, breathtaking gash across a limestone harrier in the Swiss A Ips. From its source in the Bernese Alps to its conlluence with the Rhine, the Aar River winds northward through somé of Switzerland's loveliest scenery. But few sectors can rival its passage through the Aar Gorge, a slot carved through a limestone ridge near the little town of Meiringen. Just as the river rises today from a glacier on the flanks of the Finsteraarhorn. the highest peak in the Bernese Alps, the gorge is an indirect product of glaciation. As the Ice Age came to an end somé 10,000 years ago, torrential runoff water from melting glaciers eroded a deep, narrow chasm through the limestone barrier. The result is truly spectacular. Although the gorge is scarcely 1 mile (1.6 kilometers) long, it is bounded by sheer clifTs up to 165 feet (50 meters) high. And at the bottom the cleft in places is no more than three feet (one meter) wide. ? ABIOD VALLEY. In the tower part of the valley, barren plateaus contrast with the lush greenery in oases irrigated by the A Igerian river as it descends toward the Sahara. AAR GORGE. The Aar River churns between the sheer walls of the gorge. carved when melting glaciers released torrents of water "t the close of the last ice age. Abiod Valley • Algéria • Map: page 24, D-2 Near the northem fringes of the Sahara, a ribhon of greenery • traces the course of a life-giving river. The Aurés massif, a rangé of the Saharan Atlas in northeastern Algéria, has long been a formidable barrier to travel. Lines of rugged clifls bordér the mountains on the north; to the south they slope down toward a Saharan basin that lies below sea level. One of the few passes across the massif is the Abiod Valley, a route that has been known since Román times. The Abiod River rises near the foot of Djebel Chélia ("Shield Mountain"), which, with an elevation of 7,638 feet (2,328 meters), is the highest peak in northern Algéria. Flowing southward toward the Sahara, the river winds through a valley lush with greenery nurtured by its waters. Plentiful precipitation on the high peaks of the Aurés sustains the flow of Ihe Abiod River. Djebel Chélia and other summits are covered by snow for three months of the year. and rainfall is substantial in other seasons. The highlands bordering the upper valley have a distinctly Mediterranean look. Dense forests of oaks, pines, and ancient cedars mantle the slopes. But beyond the narrow Tighanimine Gorges, where the walls bear an inseription left by Román legions, the scene begins to change. The forests give way to low shrubs. and eventually they too disappear. But the valley itself is dotted with oases watered by the Abiod. The most beautiful is at the village of Rhoufi. where stark cliffs and barren plateaus contrast with the greenery on the floor of the valley. In addition to groves of date palms, there are orchards of figs. pomegranates, and apricots, as well as plots of vegetables and flowers. A road on the rim of the cliff overlooking the valley provides travelers with spectacular views of the oasis. Other villages dot the valley farther downstream, but by now travelers are aware of hot desert winds blowing in from the south. Finally. beyond the last few scattered oases, the Sahara, whose influence has long been lelt. slretches to the horizon. And there the life-sustaining waters of the Abiod. reduced to a trickle, at last are completely absorbed by the parched desert sands. ?