Most industrial areas are also located in southern region. The fertile central valleys (3,600 - 8,500 ft) are covered by verdant coniferous and deciduous forests and dotted with numerous monasteries, temples and dzongs. Western Bhutan's major valleys of Ha, Paro, Thimphu, Punakha / Wangduephodrang are intensely cultivated. The people in these valleys are well-to-do and they build large homes of rammed earth in which several generations often live together. The formidable Black Mountains, rising to over 16,000 ft forms a natural boundary between Western Bhutan and Central Bhutan. Central Bhutan is made up of several districts where different dialects are spoken. Khyeng, in the south, is covered by semi-tropical jungle and is famous for its bamboo and ratten ware. Further north is Trongsa, home of one of Bhutan's most impressive dzongs. Bumthang's four valleys, between 8,530 - 13,000 ft with their picturesque countryside, beautiful coniferous forests and numerous Religious sites are often known as the "Heart of Bhutan". Eastern Bhutan, home of the Sharchops ("people of the east"), is generally warmer. The eastern women are renowned for their weaving skills and produce fine textiles of silk and cotton. Northern Bhutan, lying largely above 11,500 ft is region of glacial valleys, alpine meadows and is home to the semi-nomadic yak-herders of Lingshi, Laya and Lunana, have almost no contact with Western civilisation and trade only in bartered goods. Towering above this magnificent trekking country are the eternal snow-clad peaks of the majestic Jhomolhari, Jichu Drake and Gangkar Puensum, rising to over 23,000 ft.