Wikipedia Page
Wikipedia Encyclopedia on the Festival
You can find a very comprehensive article about the festival at the following address: https://fr.wikipedia.org/wiki/Festival_Crescendo. General information, history; there is a wealth of information available.
Summary
The Crescendo Festival is an annual event dedicated to progressive music (progressive rock, progressive metal, psychedelic rock) in Saint-Palais-sur-Mer, France, since 1999. Free of charge and managed by an association with the help of volunteers, it attracts nationally and internationally renowned artists, as well as 3,000 to 4,000 spectators per night over three days, making it one of the main progressive music festivals in Europe. The festival has evolved since its inception, offering outdoor concerts on the Esplanade du Concié facing the Atlantic Ocean. For more details, you can consult the article on Wikipedia.