1978 Lufthansa job not the biggest
There have been many larger robberies in U.S. history than the Lufthansa job, and they've all been perpetrated by the U.S. federal govt. OK, that's arguable, but there's one very straightforward case that is easy to explain, quantify, and understand.
In 1933, President F.D.Roosevelt signed Executive Order 6102 "forbidding the Hoarding of Gold Coin, Gold Bullion, and Gold Certificates within the continental United States". There were some exceptions allowed but as a percentage that amounted to very little. There are various estimates of the amount of gold turned in for the $20;67 offered by the govt for each Troy ounce of gold. The Treasury won't say, of course, as it seems we Merkins can't be trusted with that sort of information. I'll use the lowest estimate of 1.8 million Troy ounces (56 tonnes) although some sources say it could have been several hundred tonnes.
The robbery was two-part. First was the confiscation of the gold itself, albeit gold holders were paid $20.67 per oz. The second and most egregious part was that immediately after the govt got its greed paws on the gold they raised the gold exchange rate to $35 per oz. If it were allowed, which it wasn't, purchasing gold with dollars would cost $14.33 more per ounce than a few months earlier.
Do the multiplication and you'll find that gold holders had been robbed of $25.8 million - but that's in 1933 dollars. Using the extremely conservative (and highly suspect) Consumer Price Index price inflation figures from that same larcenous govt, applying the 1933 to 2012 rate of 1,680% to that $25.8 million means that the robbery of gold holders by their own govt would be over $430 million today.
So, that Lufthansa job was small change. It takes a govt to pull the really big robberies.