It was an unprecedented attack years in the making, with some last-minute misdirection meant to give the operation a powerful element of surprise.

A notable event occurred between early Sunday and early Monday, when at least six vessels diverted their courses.

Satellite images analyzed by The New York Times show the extent of damage at the three nuclear facilities hit by the United States. Fordo is Iran’s most critical nuclear enrichment facility, housed deep inside a mountain to shield it from attacks.