The collapse of the twin towers (September 11 2001);
The opening ceremony of the Special Olympics in Dublin (June 21 2003);
The Indian Ocean earthquake/tsunami (December 26 2004);

Perhaps because at least 2 of these were such major global events, people ended up flicking around all over the place from RTÉ to BBC to Sky to the internet to whatever that no one programme garnered enough of a rating (I know that’s what I did on both of these occasions).

It is interesting to note, however, that all of the top 9 are purely entertainment/sport, and of no real historical or political import. Just saying, like.