For most of history people argued about how we see. Plato and others thought the eye sent out fiery rays that touched objects, a view called extramission. Empedocles and later Aristotle held the reverse, that light and images from objects entered the eye, called intromission. The Arab polymath Ibn al-Haytham settled the debate around 1000 CE in favour of intromission, using experiments with a camera obscura to study how light travels. A medieval diagram in an Arabic manuscript, dating to 1407, shows the eye, the optic nerves, and the brain, reflecting this long tradition of commentary on optics. Ibn al-Haytham's work is regarded as the foundation of modern optics.

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.