Supporters fom San Juan cheer up the rowers. Donostia (Basque Country). September 13, 2015. This Challenge is one of the oldest and most famous rowing races along the Bay of Biscay, held annually in the Kontxa bay. It takes place on the first two weekends in September and regularly draws crowds of people. Men's challenge has 8 rowing teams and it was first held in 1879. Since 2008, women rowers have their competition with 4 rowing tems. (Gari Garaialde / Bostok Photo)