Seville is the capital of Andalusia and Spain's fourth most populated city: 684,000 inhabitants in the municipality and more than 1.5 million in its metropolitan area. It is the seat of the Junta de Andalucía and the economic, cultural and religious heart of southern Spain.
It sits on the banks of the Guadalquivir, Spain's only navigable river. Heir to Roman Hispalis and Muslim Isbiliya, after the Castilian conquest it became the exclusive port for trade with the Americas for two hundred years — and that explains much of its monumental wealth. Don't miss: the Cathedral (the largest Gothic cathedral in the world) and the Giralda, the Mudéjar Real Alcázar, a UNESCO World Heritage Site, the Plaza de España, the Torre del Oro, and the Triana neighbourhood across the river. Italica and the white-village route make great day trips.
Seville is the city of flamenco, tiles, courtyards, the April Fair and Spain's most spectacular Holy Week. And, in summer, of extreme heat: 45 °C is possible in July and August.
Three days is the sweet spot. The best time to visit is March-April (Holy Week and the Fair if you like events) and October-November: skip July and August without regret, unless you come ready to live by night.