Microwave cooking came from radar. The cavity magnetron, a valve that produced short-wavelength microwaves, was crucial for World War II radar, and in 1945 Percy Spencer, an engineer at Raytheon, noticed that microwaves from a radar set melted a candy bar in his pocket. He then deliberately cooked popcorn and an egg, and built a metal box to contain the energy. The microwaves make polarised water molecules rotate in the alternating field, which heats food from within. Raytheon's first commercial Radarange, in 1947, was almost 1.8 metres tall and cost about as much as a car.

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.