a mystery to (one)

Something that is difficult to understand. Why she walked out in such a huff this morning is a mystery to me! She was acting normally before that. It was a mystery to scientists where the birds migrated to until they banded some of them and tracked their movement.

Common Names:

Name	Pronounced	Usage
Patroclus	-	Greek Mythology (Latinized)
Rafaela	-	Spanish, Portuguese, Macedonian
Heleena	HE-le:-nah	Finnish
Eileifr	-	Ancient Scandinavian
Perry	PER-ee	English
Cirillo	chee-REEL-lo	Italian