Wikipedia
Ibilaldia meaning trip, journey, or march in English is a festival organized every year the last Sunday of May or first of June to help the ikastolak (schools in the Basque language) in Biscay, Basque Country in Spain.
Ibilaldia is essentially a volunteer walk around a circuit of 5-10 kilometers, that is surrounded by food stands and entertainment, and walkers sometimes make the walk in support of an organization. The money they collect it is used to help the Basque schools in the province of Biscay. It is celebrated too to reinforce Basque culture and language. As a solidary fest, everything is organized by the Ikastolas. Each year a different village is the organizer. Parents, teachers and students help to have everything prepared for the main day.