Santiago de Compostela is the capital of Galicia —around 100,000 people— and one of the world's great pilgrimage destinations for a thousand years: this is where the Camino de Santiago ends, before the tomb of the Apostle.
Everything revolves around the Cathedral and Obradoiro Square, where pilgrims complete their journey. Around it spreads a stone old town of arcades and squares, a UNESCO World Heritage Site and one of the best preserved in Europe. Don't miss the Mercado de Abastos, the second most visited spot, or the view of the towers from Alameda Park.
Santiago is also the gateway to Galicia: the Rías Baixas, the Costa da Morte and A Coruña are all nearby. The city is seen well in one or two days, and it's famous for its student atmosphere and its food (octopus, seafood, tarta de Santiago).
The best time to visit is May to October; the Galician climate is rainy, so always bring a layer and an umbrella. In Holy Years (when 25 July falls on a Sunday), visitor numbers soar.