6 megatons ... It's really chilling we could unleash such power on demand.
Definitely more than 6 megatons.
"Still, the tremendous energy of this latest explosion, which NASA estimated to be equivalent to five to six million tons of TNT, is unlike any seen in recent decades."
I think the OP was referring to the fact that as humans, we have the capability to create bombs that far exceed 6 megatons. I believe the largest nuclear blast was 50 megatons.