Hasok Chang tells the story of how the 18th-century minister and chemist Joseph Priestley became fascinated by the bubbles rising from fermenting vats at a brewery near his chapel in Leeds. He collected the gas, found it could be dissolved in water to make a refreshing fizzy drink, and that this made him famous across Europe. His work with different airs led him to produce oxygen, which he called dephlogisticated air because of his belief in the phlogiston theory. He also found that mice lived longer in enclosed spaces when a mint plant was present, effectively discovering photosynthesis. Priestley's research helped establish that air is a mixture of gases, a key step in understanding the air we breathe.

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.