Statistically, attending a weekly worship service is a remarkably safe thing to do. Global annual attendance totals many billions; the number of people killed in attacks on individual houses of worship in any given year is generally less than a few hundred. But an ambush Thursday targeting one of the nation’s largest synagogues — the latest in a spate of recent attacks targeting religious buildings — has intensified fear among clergy and worshippers worldwide. Here is a list of some of the notable attacks that have occurred on houses of worship in the past 15 years. United States March 12,...