La Profecia (1976)

Rome, June 6th, 6 AM. To spare his wife, Katherine, from the heartbreaking news of their first-born son's tragic death during childbirth, Robert Thorn, the United States ambassador to the United Kingdom in London, secretly replaces him with an unknown orphaned baby. As the adopted child, Damien, grows up in their opulent home, eerie and unsettling events unfold around him. When a priest warns the worried father that Damien is evil, Thorn dismisses it as the ravings of a lunatic. However, as the sinister occurrences escalate, Thorn embarks on a chilling investigation into Damien's mysterious origins, along with a determined reporter. But if their innocent 5-year-old son is indeed the one prophesied to bring about the end of the world, who will stand in his way?