The Northern chain is formed from the massif of the Cuchumatanes Altos (3993 m), Sierra de Chuacús (2651 m) and Sierra de las Minas (3140 m). To the north of the mountain is the limestone plateau of Petén, a flat region rich in forests, continuation of the Yucatan peninsula in Mexico. The waterways of Guatemala are generally short, particularly those flowing into the Pacific Ocean, the largest river in the country is the Motagua (approximately 400 km long), which flows into the Gulf of Honduras in the Caribbean Sea, another important river is the Usumacinta, which marks the border with Mexico; between the lakes, the largest is Lake Izabal (590 sq km). Agriculture is the most important economic sector of Guatemala, are produced coffee, bananas, sugar cane, corn, rice, beans and wheat. Important also are wood and breeding pigs, sheep and cattle. A certain importance is also covered by the mining sector are extract salt, zinc, lead, antimony, nickel, tungsten and oil. The most developed industries are those related to the processing of agricultural products such as sugar mills, breweries and for the processing of coffee. Remarkable also the tourism, thanks to sites such as Tikal, Lake Atitlan, Antigua Guatemala.