What if Humans Could Look into the Past as if Watching a Movie

"The greatest tragedy in mankind’s entire history may be 

the hijacking of morality by religion."

-Arthur C. Clarke, Credo (essay)

The late Sir Arthur C. Clarke describes in Childhood's End (1953) some plausible consequences of  the ability to look into the past and view the true history of humankind, raw and untainted by millennia of editing by men to suite their needs.  (Yes, I mean men, not man.)

The book describes a fascinating scenario in which a benevolent and seemingly omnipotent race of aliens, referred to as the Overlords, invades Earth.  The Overlords impose a simple set of rules, which together with generous gifts of scientific knowledge and technology help create a near-utopia.  Wars and violence, poverty, suffering, and even cruelty to animals are a thing of the past.  One gift in particular from the Overlord ambassador had a profound effect on religion.

The instrument he handed over ... was nothing more than a television receiver with an elaborate set of controls for determining coordinates in time and space. ... One had merely to adjust the controls, and a window into the past was opened up.  Almost the whole of human history for the past five thousand years became available in an instant.