President Ronald Reagan once famously said that a stack of $1,000 bills equivalent to the U.S. government's debt would be about 67 miles high.

That was 1981. Since then, the national debt has climbed to $14.3 trillion. In $1,000 bills, it would now be more than 900 miles tall.

In $1 bills, the pile would reach to the moon and back twice.

The United States hit its legal borrowing limit on Monday, and the Treasury Department has said the U.S. Congress must raise the debt ceiling by August 2 to avoid a default.

The White House is trying to hammer out a deal with lawmakers to cut federal spending in exchange for a debt-limit increase.

Most people have trouble conceptualizing $14.3 trillion.

Stan Collender, a budget expert at Qorvis Communications, said the biggest sum most Americans have ever handled -- in real or play money -- is the $15,140 in the original, standard Monopoly board game.

The United States borrows about 185 times that amount each minute. (read more)