SOS began in German maritime radio regulations that took effect in April 1905. It became an international standard when it was included in the service rules of the first International Radiotelegraph Convention, signed in 1906 and effective from July 1908. In Morse code it is written as three short signals, three long and three short, and it is a procedural signal that marks the start of a message asking for help when loss of life or serious property loss is imminent. Other prefixes were used for mechanical breakdowns and medical requests. SOS remained the maritime radio distress signal until 1999, when it was replaced by the Global Maritime Distress and Safety System, though it is still recognised as a standard distress signal with any method. Its pattern also reads the same upside down, an advantage for visual recognition.

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.