Econmy

Public debt:
58.9% of GDP (2010 est.) country comparison to the world: 36 53.5% of GDP (2009 est.) note: data cover only what the United States Treasury denotes as "Debt Held by the Public," which includes all debt instruments issued by the Treasury that are owned by non-US Government entities; the data include Treasury debt held by foreign entities; the data exclude debt issued by individual US states, as well as intra-governmental debt; intra-governmental debt consists of Treasury borrowings from surpluses in the trusts for Federal Social Security, Federal Employees, Hospital Insurance (Medicare and Medicaid), Disability and Unemployment, and several other smaller trusts; if data for intra-government debt were added, "Gross Debt" would increase by about 30% of GDP

USA

At 3.79 million square miles (9.83 million km2) and with over 308 million people, the United States is the third or fourth largest country by total area, and the third largest both by land area and population. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries.[6] The U.S. economy is the world's largest national economy, with an estimated 2009 GDP of $14.3 trillion (24% of nominal global GDP and 20% of global GDP at purchasing power parity).

USA

The terrain of the US includes mountains, forests, grasslands, deserts, lakes, rivers and coastline. The Grand Canyon, a gorge created by the Colorado River, is one of the most spectacular sights in the US.
The varied landscape and weather conditions produce many different types of flora. Plant life, bird species and animals are conserved in the National Parks. Animals include bears, moose, deer, raccoons, chipmunks and alligators.
National Parks on the World Heritage List are Carlsbad Caverns National Park, Grand Canyon National Park, Everglades National Park, Great Smoky Mountains National Park, Mammoth Cave National Park, Olympic National Park, Redwood National Park, Yellowstone National Park and Yosemite National Park.