In the 15th century the Inca Empire rose to annex all other nations in the area. Led by their, sun-god king, Sapa Inca, they slowly conquered what is now Peru, and built their society throughout the Andes cultural region. The Incas spoke the Quechua languages. The Incas used the advances created by earlier Andean societies. Incas have been known to have used abacuses to calculate mathematics. The Inca Empire is known for some of its magnificent structures, such as Machu Picchu in the Cusco region. The empire expanded quickly northwards to Ecuador, Southwards to central Chile. To the north of the Inca Empire remained the independent Tairona and Musica Confederation who practiced agriculture and gold metallurgy.