> The fast-moving fire is officially the second-largest in state history and the biggest single fire on record.
So which is it?
This second paragraph of the article clarifies this. The largest ever fire was last year's August Complex. It was called a complex because it was a merger of several smaller fires. This fire is the largest ever "single fire" (having a single source) and the second largest fire of any kind (single or complex).
> Many parts of the world are on fire right now, but California is in a league of its own.