Natural rubber is sticky when warm and brittle when cold, which limited its use. In 1839 Charles Goodyear accidentally dropped a mixture of rubber and sulfur onto a hot stove, and noticed the result was stronger and resisted heat better. Heating rubber with sulfur creates cross-links between its long polymer chains, so the material holds its shape rather than melting into goo. This process, called vulcanization, makes rubber elastic over a wide range of temperatures. The method made rubber practical for tyres, seals, hoses and many other everyday products.

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.