Final answer:
The main purpose of the STUXNET virus was to destroy nuclear facilities by manipulating the operation of centrifuges used in uranium enrichment.
Step-by-step explanation:
The main purpose of the STUXNET virus was to destroy nuclear facilities. STUXNET is a malicious computer worm that was discovered in 2010 and specifically targeted industrial control systems used in Iran's nuclear program. It was designed to infiltrate these systems and manipulate the operation of centrifuges used in uranium enrichment, causing physical damage to the facilities.