December 21 is the winter solstice, but the Sun's position, aka Horus, dies and remains in a very low horizon for about 3 days, then on the 25th he is born again.

Also other Astrotheology myths associated but we get Hour and Horizon from Horus.

In Spanish ¿Qué Hora es?

Literally, Where is Horus? Or What hour is it? More appropriate is where it's the Sun.