We're starting today's show in Northern Europe. The northeastern part of Norway borders the nation of Russia. That line is about 180 miles long and it's near there that about 300 U.S. Marines are participating in military training exercises with Norwegian troops. Why?
The U.S. and Norway are members of NATO, the North Atlantic Treaty Organization. It was formed in 1949 by European countries and the U.S. It was sort of guard against the Soviet Union, and the army is positioned after World War II in Eastern and Central Europe. The NATO treaty says that an attack against one NATO country is an attack against all of them, and that other member countries would come to help.
So, with tensions today increasing between Russia and several Western nations, including the U.S., military training and maneuvers on both sides is on the rise.
NICK PATON WALSH, CNN SENIOR INTERNATIONAL CORRESPONDENT: War just got very cold again for these U.S. Marines, training with tanks in Norway, on the eastern borders of a NATO that suddenly nervous once more.
They're moving forwards now towards the fake enemy positions but these kind of exercises, since Russia's moves in Ukraine, have taken on a new kind of realism and urgency.
In January, 300 Marines will move to Norway permanently. That's how worried about Moscow's intentions they are.
For now, a unit from North Carolina are readying these Abrams tanks, normally stored deep in caves but now the furthest north of the Arctic Circle they've ever been.
After Iraq and Afghanistan, these are old new war games about protecting Europe and they know that when the enemy isn't role-playing, it will probably by the newly-emboldened Russian military.
UNIDENTIFIED MALE: In 2014, that was a clear sign that Russia has stepped into an area where they are willing and able to use military. You know, suddenly we have changed focus from what was going on, in particular, in Afghanistan, and to collective defense — national defense.
WALSH: A change in focus somebody's watching. Norwegian police investigating 10 sightings of medium-sized unidentified drones over these exercises. And at a furthest point north of the border you can go, it's an open game of watching a Russian helicopter land, rare here.
It's not really a Russian invasion they worry about here but, rather, the sort of separatist uprising Russia fomented in Ukraine — little green men with guns creating trouble.
We're heading out with the Norwegian border patrol towards their frontier with Russia, a presence on the ground being vital for them and ensuring nothing untoward happens with their large, at times unfriendly, neighbor.
That's really the reason the Norwegian and American tanks you saw earlier to be sure that even out here in the empty pines and crisp snow, no matter what the Trump presidency brings, there's enough muscle already here to enforce NATO's promises of collective security.
Do you see Russians at all?
UNIDENTIFIED MALE: Uh, it happens. You just salute them.
WALSH: Would you like to talk to them if you could?
UNIDENTIFIED MALE: Probably, but it's illegal.
WALSH: Very strange to hear Norwegians, NATO members, talk so vividly again about the Russian threat.
The constant and real backdrop to this survival training happening tonight under a staggering display of the northern lights.