Colombia was once covered in dense jungle but has since cleared much of the land for agriculture, notably coffee which is one of its biggest exports. It is home to diverse wildlife like caimans, jaguars, anacondas and poison dart frogs. Spanish explorers first arrived in 1500 but did not establish settlements until 1525, and after independence it became the large country of New Granada, with Indians and Africans initially working as slaves on farms and plantations.