Tooth enamel keeps a chemical record of what an animal ate and drank while its teeth formed, and because it does not change afterwards, it can survive for millions of years. Trees and grasses use photosynthesis in slightly different ways, leaving distinct chemical signatures in the animals that eat them. Analysing fossil teeth from Ethiopia's Afar region shows that about 4 million years ago the area had wooded rivers, lakes and grassy plains, and that around 2 to 3 million years ago it shifted toward open grassland. Australopithecus afarensis, the species of the famous fossil Lucy, had mixed diets of fruit, leaves and roots rather than relying on grass.

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.