The occupation ended on Nov. 15 when police moved in, took down tents and arrested about 200 protesters. The movement sparked similar protests in other cities around the globe.

Worldwide in 2011, natural disasters, led by the March 11 Japan earthquake and tsunami, took a $350 billion chunk out of the economy, according to reinsurer Swiss Re Ltd. Insurers were, in a way, lucky, with Swiss Re saying they are on the hook for only $108 billion of those losses.

The Japanese temblor and giant wave, which set off the Fukushima nuclear power-plant meltdown, amounted to the costliest of the calamities, with more than 15,000 dead and 3,400 missing, according to Japan's National Police Agency, and $35 billion in insured damages.

One month before, a magnitude-6.3 quake struck Christchurch, New Zealand's second-largest city, toppling buildings, trapping office workers and killing 181 people. Damage was estimated at $12 billion.

Torrential Rain

The U.S. took a beating from natural disasters as well, suffering $52 billion in damage through November, according to the federal National Climatic Data Center.

The biggest hit came from tornadoes roaming across the Ohio Valley and Southeastern U.S. in April that killed 321, pummeled metropolitan areas such as Tuscaloosa, Alabama, and Chattanooga, Tennessee, and resulted in $10.3 billion in losses. In August, Hurricane Irene dropped torrential rain across Connecticut, Vermont and other parts of the Northeast, resulting in flooding that caused at least 45 deaths and $7.3 billion damages, the center said in a report.

Then Virginia and much of the East Coast were shaken by a 5.8 magnitude earthquake that rattled the ground in more than 11 states, though it caused minimal damage. The tremor, whose epicenter was 84 miles southwest of Washington, was the largest to strike Virginia since 1897.

Debt Crises

While worldwide natural catastrophes garnered headlines, world leaders sought to avoid financial disasters. The European debt crisis, simmering since late 2009, escalated in April as Portugal joined Greece in seeking a bailout; Ireland followed in November. With hundreds of billions of dollars in sovereign debt and the stability of Spain and Italy in question, European leaders on Dec. 19 shored up their anti-crisis arsenal, channeling 150 billion euros ($196 billion) to the International Monetary Fund.

Prospects that the euro zone could fall apart have been at the heart of world stock market volatility. The costs would be "horrific," Paul Donovan, deputy head of global economics at UBS AG, told Bloomberg Television Dec. 16, risking "a global depression on the scale of the 1930s."