The arson has not been solved, but many believe the incident is linked to racial tension.

CNN: U.S. attorney: Nooses, beating at Jena High not related

"The chicken-and-game problem has not been solved, " he said of the need for both game software and machine hardware.

NPR: Nintendo Chief Rules Out Price Cuts For Wii U

Europe's crisis has not been solved.

ECONOMIST: Employment springs to life; will it fade again?

Either way, Sir Mervyn noted that Greece has a solvency problem that has not yet been solved.

BBC: Why UK banks are not immune to eurozone woes

Not every problem has been so deftly solved.

NEWYORKER: Man Behind the Curtain

Not a single one of these cases has been solved.

CENTERFORSECURITYPOLICY: Russia's emerging autocracy

Not one of dozens of gangland killings since 2001 has been solved.

ECONOMIST: Bulgaria, Romania and the EU

They are not currently solved, but it is unclear if this is because no solution has yet been found or because none exists.

ECONOMIST: Computer science

It was not fixed in 2010, it has not been fixed in 2011, and every other year will be just like the prior one until it is solved, painfully or otherwise.

FORBES: Here's Why Greece Leaving The EU Could Cause Another Depression