Monday = Moon's day (Germanic root for "moon")
Tuesday = Tiw's day (Tiw = "god," from the same Indo-European root as "theos"/"deus")
Wednesday = Odin's day
Thursday = Thor's day
Friday = Freya's day (Freya, spelled several ways, is Odin's wife)
Saturday = Saturn's day
Sunday = Sun's day (also a Germanic root)

So a strange mixture of Germanic and one Latin.

In Spanish it's all Latin:

Lunes = luna's day
Martes = Mars
Miercoles = a version of Mercury
Jueves = a version of Jove
Viernes = a version of Venus
Sabado = from Latin for sabbath
Domingo = from Latin for lord
MACTECH ubi dolor ibi digitus