As of July 2012, the United States combined public debt reached $15.93 trillion. We found this visualization to help put that number into perspective.

Of that number, around 50% is owned by foreign investors. China is the largest single holder of U.S. government debt, owning around $1.2 trillion in bills, notes, and bonds.

In total, China owns about 8 percent of publicly held U.S. debt. Of all the holders of U.S. debt China is the third-largest, behind only the Social Security Trust Fund's holdings of nearly $3 trillion and the Federal Reserve's nearly $2 trillion holdings in Treasury investments, purchased as part of its quantitative easing program to boost the economy. - US Government Info

While this political cartoon makes light of the situation, what are the dangers of U.S. debt, foreign investors, and raising the debt ceiling?