Sleep paralysis is a state, while falling asleep or waking up, in which a person is conscious but completely unable to move. Episodes often bring hallucinations that people hear, feel or see, and these frequently cause fear. Each episode usually lasts only a few minutes, and it can happen once or repeatedly. It can occur in healthy people, in people with narcolepsy, or run in families through specific genetic changes. Triggers include sleep deprivation, psychological stress and irregular sleep cycles. The underlying mechanism is thought to be a fault in REM sleep, the stage when dreaming happens and the body's muscles are normally switched off. Between 8% and 50% of people experience it at some point, and about 5% have it regularly. It has been described throughout history and may have helped inspire stories of alien abduction.

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.