CARL AZUZ, CNN ANCHOR: It`s the last day of March. I hope it`s going well for you so far. I`m Carl Azuz with CNN STUDENT NEWS. Today`s show begins in Ukraine. U.S. officials say there maybe tens of thousands of Russian troops near Ukraine`s eastern border. Russia annexed Crimea, formerly a region of Ukraine earlier this month. After Crimeans voted to be part of Russia. Does Russia want to take over more of Ukraine? It says it has no intention of invading, and that its troops are just doing military exercises. But this as Ukraine on the defensive, and tensions are high.

Yesterday, U.S. Secretary of State John Kerry met with Russian foreign minister Sergey Lavrov to discuss ways to ease this crisis.

KARL PENHAUL, CNN CORRESPONDENT: Dim lights cast long shadows over this border checkpoint, just beyond thousands of Russian troops amassing. The U.S. fears its old Cold War foe may be ready to roll into this corner of Northeast Ukraine.

BARACK OBAMA, PRESIDENT OF THE UNITED STATES OF AMERICA: It may simply be an effort to intimidate Ukraine or it may be that they`ve got additional plans.

PENHAUL: A short drive into Ukraine, Vladimir Fedorok is mastering (ph) a self-defense militia made up of civilian volunteers.

They know Western powers have no stomach for war. They are digging trenches aware they may be the last line of defense if Russian tanks invade.

VLADIMIR FEDOROK, COMMANDER SELF-DEFENSE MILITIA (through translator): If we don`t learn the lessons of Crimea, then we will be a nation of idiots. The Russian hordes are coming. We are in the middle of a geopolitical struggle.

PENHAUL: Most of the men here said they have had some military training. They`ve picked up second-hand uniforms from surplus stores, but they are short on real weapons. FEDOROK: We are preparing for guerilla-style partisan war, and we`ll divide into five men squads. Our government is too passive, and we can only hope for the support of ordinary Ukrainians.

PENHAUL: It`s clear they are winning that support when you see passes-by donating supplies.

OLEK PAMFIL, VAN DRIVER: It`s our troops need some help, so I have a decision to bring food for our troops.

PENHAUL: Up the highway, a detachment of Ukrainian troops. They say they are on high alert. A T-80 tank and personnel carrier`s pointed at nearby bridge. The order - defend it or blow it up. In Ukraine`s Crimea region, the army didn`t put up a fight, not clear if things here would be any different. Intelligence experts still don`t really know if the Russians are coming. Moscow insists they are just doing drills.

Among the Ukrainian soldiers here there`s very much a sense of disbelief. They say that during Soviet times and afterwards, they trained alongside the Russians. They still very much see them as brothers in arms. But now, they are facing them down the barrel of gun.

AZUZ: Next up, it wasn`t a major earthquake by Southern California standards, but people still felt it, and it caused some damage when it hit on Friday night. It was a tremor of magnitude 5.1. This brings only minor damage in areas that are used to earthquakes where buildings are built to withstand them. But there have been more than 100 aftershocks that struck over the weekend. So, it makes sense why some folks are on edge. First quake`s epicenter, the spot on the earth`s surface right above the quake starting point was in Orange County, part of the greater Los Angeles area. Emergency officials say one person was slightly injured. The last major quake to hit here was of magnitude 6.7 tremor in 1994. That one killed dozens of people and caused $42 billion in damage.

So, if something major strikes again, how would first responders be prepared? Think people who specialize in search and rescue, emergency medicine, dangerous materials disarming explosives? You can read about how to do that stuff in a book. But there`s a place where they actually train for these scenarios, a place where a fire chief says, the pretend goes away.

UNIDENTIFIED MALE: Help!

UNIDENTIFIED MALE: We`ve got sent help, OK?

NICK VALENCIA, CNN CORRESPONDENT: About a 100 miles south of Atlanta, there are signs of disaster everywhere.

UNIDENTIFIED MALE: so, this is the replica of the Murrah Building collapse in Oklahoma, a parking garage and the garden apartment collapsed from (INAUDIBLE)

VALENCIA: Welcome to Guardian Centers, a new training facility for first responders. For this pros, it`s kind of like a doomsday Disneyland. Built on the side of what once was a Cold War missile plant, the 830 acre property can recreate just about any disaster scenario imaginable.