This is an ADC news special, Queen Elizabeth II, a royal life.

I declare before you all that my her life, whether it be long or short,

shall be debated to your service and to the service of our great Imperial family.

She's turned out to be probably beyond all measure,

the most effective constitutional monarch that the United Kingdom and the Commonwealth has ever had.

She's been monumentally effective by just being her steady self.

Monarch, wife, mother, grandmother, those are hard to juggle normally.

Put a crown on it, even harder.

It's an incredible example to me, to others, to follow.

Her leadership, her duty, her sacrifice.

That example, people took just a tiny bit of it away in their own lives.

I think the world would be a better place.

From ABC News Headquarters, here is Correspondent, Sherry Preston.

Queen, for more than half a century, Elizabeth II rained over a rapidly changing country.

The last days of a once vast empire, weathering scandals that would threaten the future of the monarchy.

For it all, Elizabeth ruled with a steady hand and a devotion to the British people.

That affection was mutual, and that's why Great Britain, today, is a nation in mourning.

The Queen's oldest son, Charles, will, of course, become king in keeping with British law of succession.

Prince William takes his father's place as first in line to the throne,

and little Prince George is now second in line, behind Prince William.

Queen Elizabeth was the longest-raining monarch in British history,

and as ABC's Terry Moran reports, one of the most beloved.

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