Wachovia Building (Philadelphia)

Consequently, the parallels range from O' at the equator to 90' at the North Pole (the small ' representing "degrees"). .If you continue to move around the Earth past the North Pole so as to travel toward the equator again, you must pass the parallels of latitude (each of which encircles the Earth east-west) in reverse order, traveling from 90' back to O' at the equator (but at a point directly opposite that of the equatorial beginning). Past the equator, you move across a second set of parallels circling the southern half of the globe, up to 90' at the South Pole and then back to O', finally at the starting point on the equator. To differentiate the O' to 90' stretch from equator to North Pole and the similar stretch from equator to South Pole, we speak of "north latitude" and "south latitude." Thus, Philadelphia, Pennsylvania is on the 400 north latitude parallel, while Valdivia, Chile is on the 40' south latitude parallel. Parallels of latitude, though excellent as references about which to build a map, cannot by themselves be used to locate points on the Earth's surface ...»