Watch: Heavy snow collapses walkway in Turkey

Russia and congressional Republicans are not yet sold on President Obama's proposal to cut America's nuclear arsenal by a third if Russia does the same. Russian President Vladimir Putin said he won't reduce his arsenal without concessions from the U.S. on missile defense systems. Major Garrett reports.

The FBI's use of drones was a secret until Wednesday, when the agency's director, Robert Mueller, answered a question from Iowa Sen. Charles Grassley during testimony on Capitol Hill. Mueller said the FBI does use drones for minimal surveillance and to get "eyes-on" details at crime scenes. Bob Orr reports.

Ben Bernanke said the economy is doing well enough that the Federal Reserve is likely to ease back on a bond-buying program that has kept interest rates at record-low rates. The prospect of higher interest rates sent the Dow down more than 200 points. Anthony Mason reports.

From the archives: Bob Orr reports on the findings of the NTSB investigation into the crash of TWA Flight 800.

While 75 percent of the planet is a relatively unchanging shade of ocean blue, the remaining surface goes through stages of green. In this NASA/NOAA imagery capturing April 2012 to April 2013, the darkest green areas are the lushest in vegetation, while the lightest could be snow covered, drought impacted or just un-vegetated rock.

In Sierra Buttes, Calif., two boys hiked up a jagged cliff and ended up stranded 8,000 feet up. The California Highway Patrol sent a chopper and had to lower a harness to carry them to safety, since climbing down was not an option. Scott Pelley reports.

In a pilot program in Tucson, Ariz., aerospace and defense contractor Raytheon is spending $100 million in hopes of inspiring future engineers and technology professionals. Anthony Mason reports.

Led by state Senate President John Morse, Colorado passed new gun control laws in March. Now, opponents of the law are trying to remove Morse from office. Barry Petersen reports.

President Obama's plan for leaving Afghanistan reached a new milestone Tuesday as the Afghan military officially took responsibility for the country's security. The White House also said it would try again to hold peace talks with the Taliban. Major Garrett reports.

In an interview with "CBS This Morning" co-host Charlie Rose, President Barack Obama defended the NSA surveillance programs and his recent decision to provide military support to the Syrian opposition in that country's civil war.

Daoud Gilani was the classic example of a terrorist sleeper agent. Born in Washington, D.C., he became radicalized and changed his name to David Coleman Headley. John Miller explains how he traveled the world on a U.S. passport, setting up terrorist attacks before he was eventually caught.

General Keith Alexander said the NSA's surveillance programs have helped stop more than 50 potential strikes since the 9/11 attacks. At least 10 of them involved homeland-based threats. Bob Orr reports.