0 something strange or not known that has not yet been explained or understood: --
How the massive stones were brought here from hundreds of miles away is/remains a mystery.
The mystery was solved when the police discovered the murder weapon.
The details of the scandal remain cloaked/shrouded/wrapped in mystery.
It's a complete mystery (to me) that/why (= I do not understand why) she married him at all!
1 a book, film, or play, especially about a crime or a murder, with a surprise ending that explains all the strange events that have happened: --
2 something strange or unknown which has not yet been explained or understood: --
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
We kunnen het stap voor stap voltooien, hoe lang de weg ook is en het kan niet worden voltooid, hoe kort de weg ook is, als je niet eens je voetafdruk markeert.