Cookouts, fireworks, and, of course, a chance to wish Uncle Sam a big "happy birthday"—the 4th of July means summer in full swing across the United States and beyond.
"In 1934 Richard Byrd was in Antarctica at his base Little America," Heintze said.
"He and his men set off fireworks in a storm when the temperature was actually quite warm for them—33 degrees below zero [-34 degrees Celsius]," Heintze said.
Such 4th of July festivities are as old as the United States itself.
In 1778, while George Washington celebrated the 4th of July with his troops in Princeton, New Jersey, Benjamin Franklin was in Paris, throwing a party for expat Americans and French elites.
Feting the U.S. was only part of the scene—Franklin also hoped to persuade the French to support the cause of U.S. independence.
4th of July Fireworks
Some 4th of July traditions are timeless.
"Parades, speeches, music, public readings of the Declaration of Independence—those were started in the days after the declaration was adopted and continue today," Heintze said.
(Listen to National Geographic World Music's 4th of July playlist.)
Fireworks, first authorized by Congress for 4th of July, 1777, are another legacy.
The American Pyrotechnics Association (APA) estimates that more than 14,000 fireworks displays light up U.S. skies each 4th of July.
APA executive director Julie Heckman said fireworks professionals plan for about 11 months for 1 month of booming business.
"On the [retail] consumer side, the 4th is the bread, butter, meat, and potatoes of the industry," she said.
"At least 90 percent of their revenue is based on Independence Day. For the professional display industry, it's probably 75 percent."
The APA also reports that fireworks are more popular than ever, and that backyard fireworks more than doubled between 2000 (102 million pounds/46 million kilograms sold annually) and 2007 (238 million pounds/108 million kilograms).
In 2007 revenues for the U.S. fireworks industry reached an all-time high of $930 million.
4th of July Fireworks: Out With Old, In With New
Fireworks may be flourishing, but some 4th of July traditions have faded.
Nineteenth-century Independence Days featured noisy artillery salutes, as explosives left over from various wars were fired all day during the 4th of July. The practice faded as cannons aged and fell into disrepair.
"Back in the early 19th century, they also celebrated with a lot of greenery," American University 4th of July historian Heintze said.
"That was started by George Washington and his troops. Soldiers wore greens in their caps, and buildings were decorated. But as red-white-and-blue paper [became widely available], and the flag became more important, that fell out of favor."
Meanwhile, new traditions have arisen—many of which would have surely stumped the Founding Fathers.
Take Nathan's Famous 4th of July International Hot Dog Eating Contest, which will be held for the 94th time on July 4th, 2009.
Legend has it that the battle began when a group of recent immigrants wanted to prove their patriotism on the nation's birthday.
Today the event is a crown jewel in the world of competitive eating.
4th of July Foul-up: Happy 2nd of July?
"The Second Day of July 1776, will be the most memorable Epocha in the History of America. I am apt to believe that it will be celebrated, by succeeding Generations, as the great anniversary Festival," wrote John Adams to his wife Abigail on July 3, 1776.
The second U.S. president had the date wrong, but Heintze maintains that the U.S. really should observe July 2nd—the day Congress voted for independence—as Independence Day. (The signing of the Declaration of Independence didn't begin until August and wasn't complete until November.)
"They didn't have the written document completed until the 4th," Heintze said.
"When they took that document to the printer on July 4th, he printed that date on the top. And that was the broadside that was sent out to all of the new states and the generals in the field. It became widely circulated, and July 2nd was forgotten."
Americans have celebrated the 4th of July ever since, though it was not declared a federal holiday until 1941.
But if the date itself has changed, the rest of Adams's Independence Day vision remains on the mark more than two centuries later.
"It ought to be solemnized with Pomp and Parade, with Shews [Shows], Games, Sports, Guns, Bells, Bonfires and Illuminations from one End of this Continent to the other from this Time forward forever more," he wrote.
MORE 4TH OF JULY FACTS