As a documentary on Eamon de Valera’s time in America airs, historian and author Ryle Dwyer looks at how history is taught here — and explains why he did not take the subject for his Leaving Cert.

The My Lai massacre — the worst American atrocity of the Vietnam War — took place 50 years ago next month on March 16, 1968, although US citizens did not become aware of it until 20 months later when freelance journalist Seymour Hersh provided the first substantial account.