Six horses collided and were eliminated Aug. 16 from the traditional 10-horse Palio di Siena horse race that takes place annually near Tuscany, Italy, according to a report from Adnkronos International.

The 350-year-old Palio di Siena is a bareback horse race run twice during the summer around Siena’s main square. The horses run on a layer of dirt put down as extra cushion atop the cobblestone surface. The Palio consists of three laps around the track, with spectators watching from inside the circle.

Last year, a horse died during a practice session for the race. Italian equine activists have reportedly been lobbying against the historic race for years, and published reports indicate that 50 horses have died in connection with the race since 1970.

Adnkronos International reports that "six out of 10 horses ended Thursday’s race on the ground. One received a slight fracture and is expected to recover