Here's a French word that I've come across a few times now that's hard to translate...
The one that fits best IMHO is "one hell of a..." from wordreference.com
Used to describe a person, thing or situation.. it's sort of colloquial/slang... and used in a positive manner to describe something that's so crazy it's almost unbelievable. I guess "unbelievable" could be another translation for it.
Even though it sounds like "sacred" in English.. in this context it doesn't have any religious connotations. It can also be used in a religious way, though.