THE PEOPLE WHO OPERATE SONORA CAVERNS SAY THEY`RE SHOCKED AND DISAPPOINTED THAT SOMEONE WOULD VANDALIZE THE WORLD-FAMOUS "BUTTERLY" FORMATION. THE STALACTITES ARE STILL HERE, THE STALAGMITES, THE POPCORN FORMATIONS, AND THE YAWNING SPECTACLE OF THIS OTHER WORLD UNDERGROUND. BUT AT THE CAVERNS OF SONORA, THE BUTTERFLY WAS ONE OF THE MAJOR ATTRACTIONS.

Bill Sawyer/Cavern Operations -- The cave beats around this one single formation. People come from all over the world because of the butterfly.

THE BUTTERFLY WAS AMONG THE MANY HELICTITES, DELICATE SHAPES WHICH FORM FROM WATER UNDER PRESSURE SEEPING THROUGH LIMESTONE. A RECENT ACT OF VANDALISM HAS LEFT THIS THING OF NATURAL BEAUTY DAMAGED.

Sawyer -- This is equivalent to the stealing of the Mona Lisa, because this is the only known butterfly in the world.

CAVERN OPERATORS BELIEVE THEY KNOW WHEN IT HAPPENED, JUST BEFORE THANKSGIVING. SOMEONE WAS ABLE TO DISTRACT A TOUR GUIDE, WHILE ANOTHER VISITOR BROKE OFF PART OF THE BUTTERFLY`S RIGHT WING, SAYS CAVERN OPERATOR BILL SAWYER. AND HE SUSPECTS IT WAS A PRANK. BUT AT THIS POINT SAWYER SAYS THEY`RE NOT INTERESTED IN FINGERPOINTING OR PUNISHMENT. THEY JUST WANT THE PIECE BACK.

Sawyer -- There is a critical time here to be able to get this piec eback in the cave because it`s out of its environment. It dries up, shrinks.

TEMPERATURES IN THE CAVERN STAY AT A CONSISTENT 70 DEGREES FARENHEIT. HUMIDITY IS NEAR 100 PERCENT. GETTING THE PIECE BACK INTO THIS ENVIRONMENT IS KEY TO ITS RESTORATION.

THIS IS NOT THE FIRST TIME VANDALISM HAS STRUCK HERE AT THE SONORA CAVERNS. ABOUT FOUR DECADES AGO, IN THE MID 1960S, A TOURIST TRIED TO STEAL A FORMATION WHICH WAS ONCE HERE, CALLED THE TOMAHAWK. A CAVERN EMPLOYEE MANAGED TO GET THE TOURIST TO RETURN IT, AND AN ATTEMPT WAS MADE TO REPAIR IT BY GLUING IT BACK ON. HOWEVER, NOT LONG AFTER THAT SOMEONE ELSE STOLEN AND IT APPARENTLY IS LOST FOREVER. HOWEVER, THANKS TO NEW TECHNOLOGY, DAMAGE OF THIS TYPE CAN BE REPAIRED IN A MUCH MORE PERMANENT WAY.

Sawyer -- We have people all over the US, especially Jim Worker and Val Hilbreth Worker of New Mexico, and this is what they do. They`re with the conservation committee of the National Speliological Society, and they`ve repaired damaged formations all over the US. And he has the expertise to come in here and do this properly.

VISITORS SAY IT`S A SHAME SOMEONE WOULD DO THIS.

Janos Kollar/visitor from Hungary -- I`m really glad we stopped, and it`s a really spectacular cave, and it`s really sad that someone damaged it because the next generations won`t be able to see.

BUT THEY SAY THE CAVERNS OF SONORA ARE STILL A SPECTACULAR WORK OF NATURE.