The country is largely mountainous, three mountain chains crossing it from north to south, the Cordillera of Guanacaste, the Cordillera Central and the Cordillera of Talamanca, between the last two is the Meseta Central, a fertile plateau 1000 metres high on average, where are the major population centres of the country. The Cordillera of Guanacaste and the Cordillera Central have mainly massive volcanic peaks including Tenorio (1920 m) and the Miravalles (2028 m) in the Cordillera of Guanacaste, the Poás (2704 m), Turrialba (3329 m) and Irazú (3432 m) in the Cordillera Central. The highest peaks of Costa Rica are found in the southern Cordillera of Talamanca where lies the Terbi (3761 m), and the highest mountain in the country, Chirripó Grande (3820 m). The main river in the country is the San Juan, which marks the border with Nicaragua and flows in the Caribbean Sea. Agriculture is the most important economic sector of Costa Rica, bananas and coffee are the main crops, followed by cotton, tobacco, cocoa, rubber and sugar cane, timber and breeding of cattle are also important. Costa Rica is the most industrialized country in Central America, it is mainly small businesses related to the processing of agricultural products. Increasingly important is tourism, especially eco-tourism in the many national parks of the country.