Porto's midsummer festival is one of Europe's great street parties and the city's most beloved night of the year. On the eve of St John's Day, the entire population takes to the streets armed with plastic hammers to bop strangers on the head (a tradition nobody can fully explain) and garlic flowers to wave under people's noses. Giant sardines are grilled on every corner, cheap vinho verde flows freely, and the night builds toward a fireworks display over the Douro River at midnight that lights up both banks simultaneously. The Ribeira waterfront and Vila Nova de Gaia across the river are the epicentres. It's anarchic, warm, and completely Porto.
The plastic hammer tradition is good-natured — join in. The grilled sardines are essential. The viewpoint at Serra do Pilar in Gaia gives the best fireworks vantage. Book Porto accommodation months ahead — this is the city's biggest night.