My creator is a mystery,
One that's set in stone.
My origins, my history,
Still totally unknown.
Tests of time I've had to face,
My strength and my endurance
Cause of weakness; it's your race,
But I'm free of all life currents.
Was I a calendar, a tomb, a shrine?
We've all wondered it before.
We don't know... but I'm a wonder!
I can tell you that for sure.
What am I?