did-you-kno:

You can use the crescent moon as a
compass. Imagine a line that extends
from the top point of the crescent
through its bottom point and down to
the horizon. If you are in the northern
hemisphere, you’re looking south, and
if you’re in the southern hemisphere,
the crescent points you north. Though
not exact, it works as a rough guide –
and the higher the moon is, the more
dependable the method is. Source Source 2 Source 3