São João in Porto: The Night Nobody Sleeps

Every city has a night when it drops the performance and just enjoys itself. In Porto that night is São João, the 23rd of June, and if you have only seen the fireworks photographs you have missed the point. The fireworks are the background. The foreground is about two hundred thousand people gently hitting each other on the head with plastic hammers.

The hammer thing needs explaining, because nobody in Porto can explain it. There was an older custom involving garlic flowers and leeks, tapping strangers on the head for luck. At some point in the 1970s a factory started making squeaky plastic hammers and the whole city quietly agreed this was better. Now you buy one from a street seller for a couple of euros and spend the night bopping and being bopped. It sounds exhausting. It is weirdly friendly, and within twenty minutes you stop noticing.

Dinner is sardines. Not politely, in a restaurant, but grilled on charcoal at street stalls set up in front of people's houses, served on a slice of bread that soaks up the oil, eaten standing up with your elbows out. The whole city smells of smoke and grilled fish. Add a bowl of caldo verde, maybe a bifana later, and keep moving.

Around midnight everyone drifts towards the river. The fireworks launch from the Douro between Porto and Gaia, and the best views are from the Gaia side looking back, or from the upper deck of the Dom Luís bridge if you like your views with vertigo. Then the night properly starts: concerts in the squares, dancing in Fontainhas and Miragaia, and a slow migration east along the river to watch the sunrise at Foz. The tradition is to walk until morning. Many people actually do it.

Practical notes. Book accommodation months ahead and expect to walk everywhere, because the centre closes to traffic. Do not fly the paper balloons anymore, the city banned them for fire risk, but you will see them in every photograph from before. And if someone taps your head with a hammer, the correct response is to tap them back. That is the entire etiquette.