On April 3, 1973, Martin Cooper, an engineer at Motorola, placed the first public call from a prototype handheld phone, from a Manhattan sidewalk to a counterpart at rival Bell Labs. The call used an experimental base station on a rooftop, linked to the ordinary telephone network. Cooper's law, named after him, says the number of radio conversations that can run at once in a given area doubles about every 30 months. That steady gain comes from using radio spectrum more cleverly and splitting coverage into smaller cells. Cooper is often called the father of the handheld cell phone.

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.