While all in America were watching the the Chicago riots at the Democratic Convention, or viewing live war zone broadcasts from Vietnam or were being mesmerized by the Watergate hearings on television, the Mother of God was appearing for tens of thousands to see in the land of the pyramids at a Coptic church constructed to commemorate the area in Egypt where she had come with Joseph and Jesus when they all fled from Herod. Starting in April, 1968, her apparitions of light changed the lives of thousands. Her appearances at Zeitun were astounding. She was seen by more than a million people. The apparitions were broadcast by Egyptian TV, photographed by hundreds of professional photographers and personally witnessed by Egyptian President Abdul Nasser, an avowed Marxist. The apparitions lasted for three years with numerous unaccountable healings recorded by various medical professionals. The local police, who initially thought the apparitions were an elaborate hoax, searched a 15-mile radius surrounding the site to uncover any type of device that could be used to project such images. They were completely unsuccessful. [Read more at Our Catholic Faith ...]This blog post at Approved Apparitions tells the story of the apparitions at Zeitun in more detail. You can also watch a video including statements by eyewitnesses here.
A short book about the apparitions, When Millions Saw Mary by Francis Johnston, can be read at The Holy Bible Online. This Coptic website includes a Zeitun Web Gallery with many links. You can find information about the Coptic Church here. The Coptic patriarch is known by the title Pope - confusing for Catholics!
* A note about approval of the Zeitun apparitions: everything I have seen suggests that the apparitions are approved by both the Coptic and Catholic Churches, though I couldn't find a definitive Catholic source online. My understanding is that they were initially approved by the local Catholic patriarch, and this was subsequently confirmed by Pope Paul VI.