Trivia

The Italian, Spanish and French actors all spoke in their own language, then were dubbed into the same language for each country.

Gillo Pontecorvo's last feature film.

A full scale model of the street where the terrorist attack took place is kept at Filmoteca Española, in Madrid.

Eusebio Poncela and Féodor Atkine later appeared in Werther (1986) and El Dorado (1988).