The dramatic Peruvian landscape draws adventurers from the world over. Bounded on the north by Ecuador and Colombia, on the east by Brazil and Bolivia, on the south by Chile, and on the west by the Pacific Ocean, Peru's land scale raises from seaside to some of the highest peaks in the world.
      Peru's principal natural features are its desert coast; the 40 great snow-covered peaks over 6,000 meters in altitude, and the mountain ranges they anchor. Renown and perhaps most spectacular is Lake Titicaca, which is shared with Bolivia, and at 3,809 meters above sea level, is the world's highest navigable lake.
       The Sierra is the commanding feature of Peru's territory, reaching heights up to 6,768 meters. Hundreds of permanently glaciated and snowcapped peaks tower over the valleys. The steep Pacific flank of the Andes supports only a sparse population in villages located at infrequent springs and seepages. In contrast, tropical forests blanket the eastern side of the Andes as high as 2,100 meters.
      Between these extremes, in the shadows of the great snowpeaks, lie the most populous highland ecological zones: the intermontane valleys (kichwa) and the higher uplands and grassy puna or Altiplano plateaus.
      Approximately 36 percent of the population lives in thousands of small villages and hamlets that constitute the rural hinterland for the regional capitals and trading centers. Over 15 percent of Peruvians live at altitudes between 2,000 and 3,000 meters, 20 percent live between 3,000 and 4,000 meters, and one percent regularly reside at altitudes over 4,000 meters.
     The Selva, which includes the humid tropics of the Amazon jungle and rivers, covers about 63 percent of Peru but contains only about 11 percent of the country's population. The region begins high in the eastern Andean cloud forests, called the "ceja de montaña" (eyebrow of the jungle) and descends with the rush of silt-laden Andean rivers--such as the Marañon, Huallaga, Apurímac, and Urubamba--to the relatively flat, densely forested, Amazonian plain.
      Native domesticated plants number in the hundreds and include many varieties of such important crops as potatoes, maize (corn), lima beans, peppers, yucca or manioc, cotton, squashes and gourds, pineapples, avocado, and coca, which were unknown in the Old World. Dozens of varieties of fruits and other products, despite their attractive qualities, are little known outside the Andean region.
       The climate of Peru varies widely, ranging from tropical in the montaña to arctic in the highest mountains of the Andes. The montaña region is extremely hot and humid, although at higher altitudes it is less so. For the Peruvians, there are two basic Andean seasons, the rainy winter from October through April and the dry summer in the remaining months.
     Crops are harvested according to type throughout the year, with potatoes and other native tubers brought in during the middle to late winter and grains during the dry season. The plant life of the three main geographical regions varies widely.