Pope John Paul II canceled his planned trip to Sarajevo amid some of the heaviest shooting around the Bosnian capital in months. The pope had hoped to say a public Mass there Thursday, but the Vatican said there were no "sufficient guarantees for the safety of the population" and that a papal visit now could only "add to the tensions." (The pope's planned appearance had been in doubt since he announced the idea last month, as Bosnian Serbs repeatedly warned him to stay away for his own safety.) The pontiff, who vowed to make the journey at some point, is still going to Zagreb, the capital of Croatia and the Roman Catholic center of former Yugoslavia, on Saturday. BTW: John Paul II may not make it to Bosnia, but the bulletproof "Popemobile" is parked there, just in case.