We have friends who have an amazing balcony which is oriented to the Duoro River as well as across to Gaia, and has a great view of Clerigos Tower. You can see hundreds, if not thousands, of lanterns in the night sky above the city.
What is São João?
Condensed Version:
São João is Porto's biggest party of the year: an all-night street festival on the night of June 23rd into the 24th, honoring St. John the Baptist. Basically the whole city stays up until sunrise. It is unique to Porto.
Detailed Version:
The weird part: people wander the streets bopping strangers on the head with squeaky plastic hammers (martelinhos). It's a friendly gesture, and nobody's exempt. The older tradition was to wave leeks or garlic flowers in people's faces (to bestow good luck with fertility), and you'll still see some of that.
The smell: sardines. Grills pop up on every corner and in backyards, and grilled sardines on bread with a bit of caldo verde soup and wine is the classic meal.
The plants: people buy little pots of basil (manjericos) with a paper flower and a short folk poem stuck in them. They're the traditional gift for someone you fancy.
The sky: around midnight there's a big fireworks show over the Douro River. People also release glowing paper lanterns (hot-air balloons), so the night sky fills with drifting lights. (These have become more restricted over time because of fire risk.)
The ending: crowds slowly drift toward the beaches at Foz, and plenty of people watch the sunrise there before stumbling home. The 24th is a public holiday in Porto, which makes this much easier.
It started as a pagan midsummer celebration and was later rebranded as a saint's day. It's loud, chaotic, very local, and very welcoming. If you ever go, embrace getting hammered (both kinds).
Our Experience:
We've seen a lot of things in our time, but this is the most chaotic, boisterous, heartwarming event - other than Loveland's "Mary Me and Ski for Free" - that we have ever experienced.
We walked from our apartment - red dot near Bolhão - to the orange dot above Taylor's Port Shop. The walk is almost a straight shot down the major street pictured.
So, we walked down the pedestrian street and through Praça de D. João and Aliados. What we witnessed was incredible. Bands playing, people singing and dancing, people grilling sardines, bars with DJs on their balconies and most fascinating of all was the sound of plastic hammers with squeakers. Example below. We were noobies so we had the smallest hammers which require a little more effort than the big ones so we will be purchasing different hammers next year. You can find said hammers in pretty much every store and on the streets from multiple vendors on the day of. The handles come equipped with a whistle.
A couple of amazing things from an American's perspective - were there police and GNR (state) all over? Yes. Are there bag inspections or gated areas? No. What are the officers doing? Allowing themselves to be bopped on the head - mostly by children - and bopping in return. The entire atmosphere was light and fun and absolutely addictive.
Porto allowed us all to light paper lanterns between a set period of time as there was a concern for fire danger as winds were high and we'd been pretty dry. We had so much fun lighting them and watching them ascend to the sky with our neighbors' lanterns. The sky eventually filled with THOUSANDS of them (see first picture above). Absolutely magical.
It took a bit of finesse to light the lanterns as the wind was pretty high. We now know what we did right - and wrong - so next year we will buy more lanterns.
We bailed around 23:00 opting not to go down to the River and then join the procession to the beach to watch the sunrise. Maybe next year.
On the way home, we encountered a lantern that had given up the ghost. By 6:00 the next morning, there wasn't a sign of the fact that thousands of people had partied in the streets until 4:00. We lived off this high for days. Again, this was magical and if you can come during this time, we'd highly encourage it.