As the dawning sun warmed the Albuquerque, Mew Mexico plain, not one, not two, but 500 rainbow-colored and designer-shaped hot air balloons rose at this year's Albuquerque International Balloon Fiesta, which carried the theme Earth, Wind and Flyers.

The Balloon Fiesta, which ran for nine days from Oct. 2 through Oct. 10, drew an estimated 800,000 visitors, 500 hot air balloons and 650 pilots from around the world to participate in the 39th year of the world's largest mass ascension. There were participants from 39 states and 17 countries.

The event took place at Balloon Fiesta Park, a 72-acre ballooning site. The area is unique because of a geographic phenomenon called the Albuquerque Box.

During the first days in October, the cool earth of the dry Rio Grande Valley, the cool moisture of the Rio Grande, and the dry surrounding mountains create a temperature inversion with stable, roughly 10 mph air flows in varying directions at select altitudes. A pilot can bring a balloon back to near the point of takeoff by changing altitudes to ride wind currents in different directions.

The pilot first heads southward toward downtown Albuquerque, then ascends higher where the winds return the balloon back north towards the Balloon Fiesta Park.

The hot air balloon envelopes at the Fiesta are generally made of synthetic fiber cloth – rip-stop nylon or polyester – and coated with a polyurethane sealant. The lower portions of the balloon envelope, where the fabric is near the propane heat source, is usually made from fire-resistant Nomex.

The average hot air balloon is about 80,000 cubic feet in volume and can lift a 1,200- pound payload, including basket, propane tank and burners, instruments, and passengers. The propane burner heats the air inside the envelope. As the air warms and expands, the hot air balloon rises. As the air cools, the balloon descends.

For the early morning mass ascension, each deflated, folded balloon was driven by truck to its staging location where teams of typically four people unloaded the basket, burners and envelope. The envelope is unfolded and stretched out on the ground, and the basket is attached.

A gasoline-powered fan blows air into the balloon to give it its initial shape, then the burner is turned on and the air is heated and the balloon is lifted upright and ready to ascend. Normally a hot air balloon carries a 10 to 25 gallon propane tank and consumes about 15 gallons per hour.

While most of the hot air balloons are designed with the classical inverted teardrop shape, an increasing number of balloon enthusiasts have opted for "Special Shape Balloons." At the Fiesta, there were hot air balloons in the shape of a Pepsi can, a house, Sponge Bob, a cow, and Darth Vader.

Because the balloon ascensions depend on the warming action of the sun, the events begin early. The Dawn Patrol begins sending up survey balloons at 5:45 a.m. and by 10 a.m., the morning session is effectively over for the Fiesta.

The Dawn Patrol draws thousands to their predawn ascent as the blasts of propane alight their balloons in the dark early morning sky and they take off to determine the condition of the winds.

The origins of the Albuquerque International Balloon Fiesta trace back to 1972 when a balloon rally hat attracted 13 contestants. The Balloon Fiesta began in 1978 with 278 balloons. There were no special shapes.

Ten years later, in 1988, 600 balloons were registered, including 12 special shapes. In 1998, 873 balloons were registered.

The first gathering of balloonists was in France in 1783 when the Montgolfier brothers launched a smoke-filled balloon to the delight of the French King and Queen and 40,000 spectators. The first passengers were a duck, a rooster and a lamb.

Within weeks, several pilots completed manned flights.