The Vallas, a Czechoslovakian family performing as the Bertinis, amazed audiences with their teeterboard, somersaulting and pyramid routines on the unicycle and the free-balancing, swinging split breakaway dive from the hanging perch. During the Cold War, they were the first performers the Communists allowed out of the country to come to the U.S. for a two-year tour. Today, the seventh and eighth generations continue to entertain circus audiences.