Thursday: Russia's Ukraine 'invasion', Mexican deportees return to US, slithering stones, and more...

Russia says it hasn't sent soldiers and tanks across the Ukrainian border -- but Ukrainian officials say it is, indisputably, a Russian invasion of their territory...Nine Mexican immigrants are allowed to return to the U.S. to explain why they believe they were coerced into accepting deportation...and three American scientists focus their attention, and their cameras, on the mystery of how rocks slither across the desert floor in Death Valley without human help.

Part One

Ukraine: Russia 'invasion'
According to Ukrainian officials, Russian soldiers and artillery have crossed the border. According to Russian officials, no soldiers or artillery have been sent anywhere. Ukraine's ambassador to Canada shares what he has been told about the situation.

Drunk patient privacy
A Toronto doctor wants changes to Ontario's privacy laws -- so he and his colleagues have more influence over reporting drivers who appear to be under the influence.

Hidden gold art
A German artist has buried 30 gold bars in the sand of an English beach. Now the public are searching for it.

Part Two

Slithering stones
For decades, people have let the mystery slide. But now, for the first time, scientists have solved that slithering mystery -- by filming how rocks move, and leave previously unexplained trails, across Death Valley in California.

Mexican deportees return
In a case that could have repercussions for American immigration policy, nine people who were deported to Mexico are allowed to return to the U.S. to argue they were misled by officials.