On April 30, ...

...1909, the Netherlands' Crown Princess Juliana (left, as a child), was born. She became queen in 1948 when mother, Queen Wilhelmina, retired. On April 30, 1980, Juliana stepped aside for her own daughter, Queen Beatrix I, who reigns as Netherlands' queen to this day. Juliana died in 2004.
... 1993, a man plunged a knife into the back of tennis' top woman player, Monica Seles, as she played a match in Hamburg, Germany. The attacker, an unemployed man described as "disturbed," was convicted later in the year and received a suspended 2-year sentence. The 19-year-old Seles did not return to elite tennis until 1995, and she never regained 1st place on the circuit.