Thirty years after terrorism first struck the World Trade Center, victims’ relatives and survivors are commemorating the deadly 1993 bombing that foreshadowed 9/11. Anniversary observances are planned Sunday at the trade center and at a nearby church. The explosion in an underground parking garage killed six people, including a pregnant woman. More than 1,000 people were injured. Tens of thousands fled in a harrowing evacuation that highlighted the challenges of clearing out some of the world’s tallest buildings in a fiery emergency. The blast also served as a warning of Islamic extremists...