Half an hour ago.
The Middle Heavens.
It is said that the world is divided into three different parts - the Lower Heavens, the Middle Heavens, and the Upper Heavens!
Each progressing heaven has a totally different living condition and qi density.
The higher the cultivators went, the denser the Qi is and easier it becomes to cultivate.
For instance, it is rare to see a Core Formation Realm cultivator in the Lower Heavens, and someone of that caliber is usually a high-ranked member of an organization, sect, or clan.
However, Core Formation Realm cultivators are pretty common in the Middle Heavens, and even the younger generation cultivators can get to this realm at an early age.
As for the Upper Heavens, it isn't usually in the picture - because to get to that place, one must surpass the unachievable - Great Saint Real!