I shouldn’t have been surprised that the rain didn’t stop the Dutch kids. All day it had been thunderstorming, and the forecast didn’t look so great for the evening. And yet at 5pm, hundreds of kids started arriving – many by bike – with their parents to Amsterdam’s Westerpark, a beloved city park that caters to a more residential area of the capital. Today, it functions as a starting point: volunteers coordinate registration, and groups of children gather, decked out in raincoats and eager to embark on either a 5km or a 10km excursion around the surrounding neighbourhoods.

It’s the second night of Avondvierdaagse (which literally means “four-day evening walk”) , organised by a group of neighbourhood volunteers. It’s not a race, but if children complete every night, they get medals, a bouquet of flowers and, if they’re lucky, a lot of sweets. It’s not just Amsterdam; across villages, towns and cities in the Netherlands, hundreds of thousands of Dutch people are doing the same: every year, kids spend four evenings in early summer exploring their neighbourhoods with their school friends and parents as part of the Week van de Avond4daagse. Some places had celebrated earlier; others were walking the following week. A variation of the tradition has even made its way to Suriname, one of the Dutch former colonies. There are also four-day cycling and swimming events. According to the Royal Dutch Walking Association (KWbN), which helps coordinate the events, half a million people take part every year, in 700 locations across the country, powered by tens of thousands of volunteers.