Just remember that during cold war US Government believed the US dollars bills safe from really good fakes untill they discovered in the mid nineties the "Supernotes" alledgedly
printed in north Korea since ...the eighties.
"The name derives from the fact that the quality of the notes exceeds that of the originals. Some have estimated that 1 in 10,000 bills was a counterfeit of the quality ascribed to supernotes."
It took more than ten years to spot these really good fakes
But I know it is an endless debate between believers and non believers.
Edit for picture : an average bill like this one contains more than 10.000 pictural details,
so making a copy of a dial...