Padrão dos Descobrimentos or the Monument to the Discoveries, an iconic landmark of Lisbon, near Belem Tower, located along the Tagus river where ships departed to explore and trade with India and Orient. The monument celebrates the Portuguese Age of Discovery in the 15th and 16th centuries. The pavement in front of the monument is decorated with a mosaic that was offered by the South African government in 1960 when the statues were completed, representing a compass with the map of the world charting the routes taken by the Portuguese explorers. On the right is a metallic representation of the esfera armilar; a mathematical model of the universe based on the Ptolemaic conception of the geocentric cosmos. It was this model that enabled navigators to explore the globe and to be guided by stars in the celestial sphere.