Trying to pull information out of memory strengthens it more than simply rereading the same material. Each time you retrieve something, you rebuild the memory trace, which makes it easier to recall later. This is called the testing effect, also known as retrieval practice or active recall. Tests that are harder for memory tend to produce even bigger gains, so a quiz is a learning tool rather than just a measurement.

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.