The Ukrainian Armed Forces destroyed the new Russian S-500 air defence system using American ATACMS missile. Learn about the events that took place and the details of this unique destruction.
According to Wikipedia, one S-500 system has a ~ $2.5 billion price tag and it still is unable to protect itself ;)
Destroying one with nearly any ordnance available will give you the best bang for a buck one can possibly get. The murderous thieves may find it very hard to replace these with the sanctions up, which is nice.