Pakistan extends along either side of the historic Indus River, following its course from the mountain valleys of the Himalayas down to the Arabian Sea. Bordering on India, China, Afghanistan and Iran, it is strategically located astride the ancient trade routes between Asia and Europe. Pakistan's 796,095 square kilometers of territory include a wide variety of landscapes, from arid deserts to lush, green valleys to stark mountain peaks. Geographically, Pakistan can be divided into three regions: the lowlands along the Indus in the south and east, the arid plateau of Baluchistan in the southwest, and the mountains of the north. The provinces of Punjab and Sindh, in the east and south, are well irrigated by the Indus and its tributaries. The land is fertile and produces most of Pakistan's food. This area, which includes the cities of Karachi, Islamabad (the capital), Lahore and Rawalpindi, is the most densely-populated in the country. The southwestern province of Baluchistan covers almost half Pakistan's territory. The land consists of a stony plateau, sparsely populated and very dry. Outside of the provincial capital of Quetta, travel in Baluchistan is extremely restricted. Pakistan's mountainous north contains the second tallest peak on Earth , K2 (28,250 ft., 8611 m), and over 300 glaciers. Three great mountain ranges stretch across this part of the country:the Himalayas, the Karakorams and the Hindu Kush. The region's topography is constantly changing, as frequent earthquakes help the mountains grow at the remarkable rate of 7 mm (1/4 inch) a year. Pakistan's climate varies according to elevation. April through September are the most pleasant months in the mountains, although they bring oppressive heat to the low-lying plains of the Indus Valley, where midday temperatures can exceed 40 degrees Celsius (100 degrees F). December through February are the coolest months, as lowland temperatures drop to between 10-25 degrees C (50-77 degreesF) and the air in the mountains falls below freezing. Monsoons reach the southern areas of the country in late summer, although precipitation is minimal in Baluchistan and in the north and limited in most of the interior. History and People While Pakistan as a country is relatively new, the Indus River region is known as a cradle of civilization. Archaeologists have found fossils of Homo sapiens in the area which date back 50,000 years. An urban society known as the Indus Civilization developed around 3,000 BC and flourished for a period of about fifteen hundred years. One of the reasons for the rise and the prosperity of the Indus Civilization was its situation right along a natural trade route between central Asia and the Indian subcontinent. While this position encouraged the rise of an urban trading society, it also encouraged wave after wave of invasion, making Pakistan's history a mind-boggling tapestry of successive conquests. The first of these incursions was that of the Aryans, who arrived from Central Asia around 1,700 BC, displacing the Indus Civilization and bringing Hinduism to the region. Twelve hundred years later, the Aryans yielded in turn to the armies of Cyrus the Great, and the Indus region became a part of his Achaemenid Persian empire. The next conqueror to arrive was Alexander the Great, who passed through the Khyber Pass in 326 BC, built a fleet of ships, and sailed down the Indus to conquer what is now the Punjab state. It was in the Punjab that Alexander's soldiers refused to go any further east, prompting an enormously difficult march homeward through the harsh desert regions of Baluchistan, Afghanistan, and Iran. Alexander's successors, the Seleucids, survived for about a century, until they capitulated to Ashoka, emperor of the great Mauryan empire of India. It was Ashoka who, in an act of remorse for the suffering caused by his many conquests, brought Buddhism to Pakistan (and to much of Asia). The Mauryans were then succeeded by the Bactrians, the Saka (Scythian nomads), the Parthians, and, in the 2nd century AD, by the Kushans. Kanishka, the greatest of the Kushan kings, ruled from Peshawar over an empire that stretched across much of India. As the Kushan empire declined, various Hindu kingdoms based in India asserted their power, dividing up the territory between them. Islam was introduced in the 8th century and quickly spread throughout the region. The Turkish rulers of Afghanistan invaded Pakistan as they began their conquest of India. Pakistan then passed under the control of the Muslim sultans of Delhi. Early in the 16th century, Pakistan became part of the Mughal Empire. Under the emperors Akbar, Jahangir and Shah Jahan, art and architecture flourished. By the early 19th century, the Sikhs had consolidated their power and declared Lahore their capital. Within a few decades, however, the Sikhs were defeated in battle by the English, and Pakistan became part of the British Raj. When India prepared for independence from the British in the 1940s, Muslim Indians pushed for their own independent state, and the republic of Pakistan came into being on August 14, 1947 as a Muslim homeland. Unfortunately, the birth of both Pakistan and India was marked by massive bloodshed, when violence broke out between Muslims and Hindus migrating from one country to the other. About 500,000 people are believed to have died. Pakistan's population of 128 million is one of the fastest-rowing in Asia. The two largest ethnic groups are the Punjabis, an Indo-Aryan people who dominate political and business life, and the Pashtuns, who work mainly as herders and farmers. The northern areas are home to many distinct ethnic groups, whose eclectic heritage is the result of intermarriage between local peoples and invaders from elsewhere in Europe and Asia. The official language is Urdu, and English is used extensively in business.