I've been wondering what that was called.

#1: Philtrum

Definition:

philtrum : the vertical groove on the median line of the upper lip

Example Sentence:

His chiseled features even included a well-defined philtrum.

Origin:

In Greek, the primary meaning of philtrum is "love potion" – which suggests that seductive powers were attributed to this facial feature.

Source:
Merriam-Webster