Question: can you come up with 1 successfull cartel/monopoly, which does not exist due to force( gunpoint, government)

Of course many times competing companies might make agreements to make higher prices etc, but i want to know of a successfull cartel existing over some period of time.

In an unregulated economy, there are no cartels ( my point of view)

So this discussion, as for me, can also be reduced to whether cartels really do ever exist anyway to start with. ( would like to hear some examples)

If not, then might bitcoin give rise to the possibility of successfull cartels?
Cartels is something from a static world i think, ours is very dynamic and ever changing.