Gabby Giffords Shooting

Jan. 8: Rep. Gabrielle Giffords was critically injured during an attack by a gunman in Tucson, Ariz., where six people were killed and another 20 injured. The alleged gunman, 22-year-old Tucson resident Jared Lee Loughner, was reportedly targeting Giffords, who sustained a gunshot wound to the head at point-blank range. (credit: Shaun Tandon/AFP/Getty Images)

Haiti Quake: One Year Later

File photo of Haiti. (Credit: Eitan Abramovich/AFP/Getty Images)

Jan. 12: A 2010 earthquake in Haiti that killed more than 230,000 people and caused a political upheaval continued to leave the country in ruins one year later. In addition to those killed, and the millions of others rendered homeless, over 3,600 others were later wiped out by a cholera epidemic. (credit: Eitan Abramovich/AFP/Getty Images)

Arab Spring Movement Begins in Tunisia

Jan. 14: Beginning in December 2010, widespread discontent and unrest in Tunisia led to a revolution that ultimately ousted longtime president Zine El Abidine Ben Ali. The movement began the Arab Springs protests that took place across the Mideast. (credit: Marwan Naamani/AFP/Getty Images)

Mubarak Resigns As Egyptian President

Feb. 11: Egyptian President Hosni Mubarak was forced to resign after 30 years in power, handing over control to the Egyptian military. His resignation was caused by increasing pressure from widespread, large-scale protests from thousands of Egyptian civilians. He is currently on trial for the deaths of hundreds of protesters. (credit: Peter Macdiarmid/Getty Images)

Wisconsin Teacher Protests

Feb. 17: In February, teachers banded together in protest of Wisconsin Gov. Scott Walker's proposal to limit union bargaining rights. Encampments, faculty teach-ins and student walk-outs lasted for weeks to express discontent over the changes, which were introduced as part of a budget repair bill. (credit: Mark Hirsch/Getty Images)

Japan Earthquake And Tsunami

March 11: A catastrophic tsunami caused by an undersea earthquake with a 9.0 magnitude destroyed the coast of Japan. Almost 16,000 were killed by the resulting flash floods, with thousands more injured or missing. The devastating earthquake and tsunami caused a meltdown at the Fukushima nuclear power plant. (credit: Noboru Hashimoto/AFP/Getty Images)

U.S. Sends Warplanes to Libya

March 19: Nearly 20 U.S. warplanes were part of the NATO strike operation against Libyan leader Muammar Qaddafi and his forces. The objective of the mission was to cease attacks on Libyan citizens by government forces, and to further dismantle the regime's stronghold on the region. (credit: Joseph Eid/AFP/Getty Images)

Tornado Outbreak Kills 350 People In South

April 27: A 'super tornado' outbreak in the southeastern United States caused a series of powerful storms to rip through Alabama, Georgia and Tennessee over the course of just several hours. The track spanned over 220 miles of land, reached winds in excess of 200 mph, and claimed the lives of 350 people. (credit: Mandel Ngan/AFP/Getty Images)

Obama Releases Birth Certificate

(credit: Jewel Samad/AFP/Getty Images)

Royal Wedding Of Prince William And Kate Middleton

April 29: In what was heralded as the wedding of the century, England's Prince William married his fiance, Kate Middleton, in a lavish ceremony watched by millions throughout the world. (credit: Dimitar Dilkoff/AFP/Getty Images)

Bin Laden Killed

May 1: Osama bin Laden was killed by United States Navy SEALs at his compound in Pakistan as part of Operation Neptune Spear. Afterwards, bin Laden's body was identified, then buried at sea less than 24 hours after his death. (credit: Sabah Arar/AFP/Getty Images)

GOP Debates Kick Off

May 5: The 2012 election season kicked off with a debate between GOP presidential hopefuls. Former business owner Herman Cain, former Minnesota Gov. Tim Pawlenty, and former Sen. Rick Santorum were among those who squared off during the event, which was held at the Peace Center in Greeneville, S.C. (credit: Mandel Ngan/AFP/Getty Images)

Dominique Strauss-Kahn Scandal

MAY 14: French economist and French Socialist Party member Dominique Strauss-Kahn was arrested for reportedly sexually assaulting a maid at the Sofitel New York Hotel. The validity of the claims of his accuser, 32-year-old Nafissatou Diallo, led ultimately to the caseís dismissal several months after Strauss-Kahn was arraigned. (credit: Francois Guillot/AFP/Getty Images)

Arnold Schwarzenegger Admits To Affair

May 17: Former California Gov. Arnold Schwarzenegger admitted to fathering a love child with Mildred Baena, a woman who worked as a maid for the family. Maria Shriver later filed for divorce. (credit: Jason Merritt/Getty Images For The Consulate General of Israel)

160 Die In Joplin, Mo., Tornado

May 22: A category EF5 tornado, the strongest possible tornado, devastated the Joplin, Mo., area, resulting in widespread destruction and the deaths of 160 people. The death toll made it the deadliest tornado on record in nearly 60 years. (credit: Mario Tama/Getty Images)

Anthony Weiner Scandal Leads To Resignation

June 16: Rep. Anthony Weiner resigned from Congress after accidentally posting a semi-nude photo of himself on Twitter. At first the Congressman denied it, blaming it on hackers. However, later on he admitted that it was him and that he had several online relationships with women. (credit: Spencer Platt/Getty Images)

Obama, Boehner Hold Golf Summit

June 18: President Obama and House Speaker John Boehner talked over a game of golf to work out differences over the debt-limit debate. They played against Vice President Joe Biden and Ohio Gov. John Kasich. The game was down to the wire until the 18th hole, when Boehner won. (credit: Cory Lum/Getty Images)

New York State Legalizes Gay Marriage

June 24: New York became the largest state to legalize same-sex marriage. The bill's fate was undetermined until just before the vote, which ultimately passed 33 to 29. (credit: Jemal Countess/Getty Images)

Casey Anthony Found Not Guilty

July 5: The trial that captured the nation's attention ended in an acquittal for Casey Anthony, the woman who was accused of killing her 2-year-old daughter Caylee Marie. The jury cited a lack of evidence to convict. (credit: Joe Burbank/Getty Images)

NASA's Space Shuttle Program Ends

July 21: After 30 years of forging the path to space exploration, the National Aeronautics and Space Administration (NASA) shut down its shuttle program. The retirement of the program, which made its final launch with shuttle Atlantis on July 8, was mandated by former President George W. Bush in his Vision for Space Exploration. (credit: Roberto Gonzalez/Getty Images)

Amy Winehouse Dies

July 23: Vocalist Amy Winehouse was a talent best known for the Motown-inspired song 'Rehab'. Struggling with addiction for several years, she finally succumbed and died from alcohol poisoning at the age of 27. (credit: Carl Court/AFP/Getty Images)

Congress, Obama Avoid Nation's First-Ever Default

July 31: Just before the nation almost defaulted on its debt, President Obama and Congress worked out a deal to raise the debt limit. The plan called for lower spending without raising taxes. Another result of the debates created the Super Committee, a panel of six members from the House of Representatives and six from the Senate, whose goal was to reduce the budget by $1.5 trillion. The committee failed to reach an agreement in late November. (credit: Roger L. Wollenberg/Getty Images)

Standard & Poor's Downgrades U.S. Debt for First Time

Aug. 5: Ratings firm Standard & Poor's elected to downgrade the AAA rating of the United States Treasury to an AA+. The ranking, which places America below a dozen other governments worldwide, also essentially dictates that America is not a safe investment. (credit: Mario Tama/Getty Images)

31 U.S. Troops, Most Navy SEALs, Die In Afghan Chopper Crash

Aug. 6: Insurgents shot down a helicopter with over 30 United States special operations forces on board. A total of 38 people were killed in the crash, which happened in the country's Wardak province. (credit: Shah Marai/AFP/Getty Images)

East Coast Earthquake

Aug. 23: Several states along the eastern seaboard of the United States were rocked literally by an earthquake that hit Louisa County, Va. The effects of the 5.8 magnitude quake were felt as far north as New Hampshire, affecting over a dozen states in the region in all. (credit: Michael Bocchieri/Getty Images)

Hurricane Irene Strikes U.S.

Aug. 27: Hurricane Irene, a Category 3 storm cell that lived for nine days, made landfall on the U.S. mainland. The exceptionally large storm cell ripped its way up the East Coast, causing extensive damage from Florida and South Carolina, on up to parts of Canada. (credit: Monika Graff/Getty Images)

Ten Years Since 9/11 Attacks

Sept. 11: The 10-year anniversary of the 9/11 attacks, a coordinated series of terrorist attacks that killed thousands in New York City, Washington, D.C., and Shanksville, Pa., was remembered this year. Somber ceremonies throughout the nation were held to remember those who lost their lives in the World Trade Center, Pentagon, and the hijacked flights. (credit: Timothy A. Clary/AFP/Getty Images)

Occupy Wall Street Begins

Sept. 17: The Occupy Wall Street movement began in Zuccotti Park, near New York City's financial district and iconic Wall Street. A protest of economic inequality, the movement has spread internationally, with 'Occupy' offshoots found in cities across the world. (credit: Spencer Platt/Getty Images)

'Don't Ask, Don't Tell' Military Policy Repealed

Sept. 20: The controversial 'Don't Ask, Don't Tell' policy, which banned members of the military from serving openly gay, was repealed. The policy was first instituted by former President Clinton in December 1993. (credit: Mandel Ngan/AFP/Getty Images)

Steve Jobs Dies

Oct. 5: Steve Jobs, the founder of Apple Computers, died at the age of 56 after a long battle with pancreatic cancer. Jobs' innovations gave millions of people around the world iPhones, iPads and iPods.(credit: Jay Directo/AFP/Getty Images)

Muammar Qaddafi Killed

Oct. 20: Eccentric dictator Muammar Qaddafi rose to power in the late 1960s and ruled Libya until Libyan rebels overthrew his government and ultimately killed him. Qaddafi is accused of being behind the Pan Am Flight 103 bombing over Lockerbie, Scotland, that killed 270 people. (credit: Abdullah Doma/AFP/Getty Images)

Obama Announces All U.S. Troops Will Be Withdrawn From Iraq

Oct. 21: After an occupation and war that lasted almost nine years, President Barack Obama announced that he planned to withdraw almost all combat troops stationed in Iraq by the end of 2011. The last of the troops are anticipated to leave the country by Jan. 1, 2012. (credit: Davis Turner/Getty Images)

Earth's Population Reached 7 Billion People

Oct. 31: The United Nations Population Division said that the world reached a population of 7 billion people on Halloween, though finding the exact time of day proved impossible. Only 12 years ago, the world hit the 6 billion mark, showing a sharp spike in births. (credit: Stephen Lovekin/Getty Images)

Penn State Sex Abuse Scandal

Nov. 4: Happy Valley was rocked after charges alleged former Penn State defensive coordinator Jerry Sandusky had inappropriate sexual contact with at least 10 boys between 1994 and 2009. He was indicted on 40 counts of child molestation, and the details of the investigation resulted in the firing of Penn State coaching legend Joe Paterno and resignation of university president Graham Spanier. (credit: Patrick Smith/Getty Images)

Conrad Murray Found Guilty in Michael Jackson's Death

Nov. 7: Former doctor Conrad Murray was found guilty of involuntary manslaughter after causing the death of pop legend Michael Jackson two years ago. Murray had been hired by Jackson to serve as his private physician, and was in charge of dispensing the pain medication and sedatives that ultimately proved lethal for the embattled musician. (credit: Al Seib/Getty Images)

Supreme Court To Take Up Health Care Law

Nov. 14: President Barack Obama's signature piece of legislation, the health care overhaul law, will be challenged in front of the Supreme Court. Arguments for and against the measure will be heard in March 2012, with a decision anticipated in late June. (credit: Spencer Platt/Getty Images)

Herman Cain Sexual Harassment Allegations

Nov. 28: Former presidential GOP candidate Herman Cain became the subject of national scrutiny and ridicule after a series of allegations arose stating that he had harassed several former female employees during his time as president of the National Restaurant Association. The allegations ranged from uncomfortable and sexually-charged incidents to a 13-year intimate relationship. The accusations ultimately led him to suspend his campaign. (credit: Davis Turner/Getty Images)

Virginia Tech Shooting

Dec. 8: Less than five years after violence ripped through the community at Virginia Tech, two people were killed on campus as a result of gunfire, one of whom was a campus police officer. The previous attack, which occurred in 2007, was the worst mass murder in U.S. history when 32 people were killed. (credit: Jared Soares/Getty Images)