Final answer:
The line of latitude that encircles the center of the Earth is called the equator, which is at 0 degrees latitude and divides the Earth into Northern and Southern Hemispheres.
Step-by-step explanation:
The line of latitude that runs around the centre of the Earth is known as the equator. This imaginary line divides the Earth into the Northern and Southern Hemispheres and is marked as 0 degrees latitude.
The equator is the longest circle of latitude and is significant because it is the point where the sun is directly overhead during the equinoxes in March and September.
Unlike other latitudes, it has no letter denoting a direction (North or South) because it is the very middle of the Earth's latitudinal system.
Geographically, the equator is crucial for navigation and climate patterns, while culturally, it is a point of interest and significance as it represents the line of equal day and night. It is often marked and celebrated in countries through which it passes.