Preparations are under way to celebrate Jewel Cave's first century as a national monument, according to officials at the facility.

On Feb. 7, 1908, President Teddy Roosevelt established Jewel Cave National Monument. Subsequent exploration at Jewel Cave has revealed it to be the second-longest cave in the world, with a documented length of more than 141 miles.

Superintendent Todd Suess said that the Feb. 9 celebration will include a special program, free tours and refreshments.

Events formally begin at 1 p.m., with a special program that will include honored guests and former cave explorers Herb and Jan Conn. They will talk about their 21 years of cave exploration, in which they have mapped more than 60 miles of cave passages since 1959. The caving parties led by the husband-and-wife team made more than 700 trips into the cave and logged 6,000 hours of exploring and mapping.

Refreshments will be served after the program.

Meanwhile, free tours will be offered on a first-come, first-served basis at 10 a.m., 11 a.m., 2:30 p.m. and 3 p.m. The 1/2-mile tour is moderately strenuous and follows a paved, lighted trail with more than 700 stair steps. The tour lasts about 1 hour and 20 minutes and begins and leaves the cave by elevator from the visitor center.

The cave temperature is 49 degrees, so participants are encouraged to wear a light coat or sweater and sturdy walking shoes.

Other activites are planned throughout the year in conjunction with the centennial celebration.

For updates and information about the centennial celebration plans, go to http://www.nps.gov/jeca/ or call Jewel Cave National Monument at 673-2288.