The interior highlands are the most prominent feature of Honduran topography. This mountain area makes up about 80% of the country's area, and is home to the majority of the population. Because the rugged terrain has made the land difficult to traverse and equally difficult to cultivate, this area has not been highly developed. The soil here is poor: Honduras lacks the rich volcanic ash found in other Central American countries. Until the early 20th century, the highland economy consisted primarily of mining and livestock.