Latitude lines, also known as parallels, are imaginary horizontal lines that run around the Earth. They measure the distance north or south of the Equator, which is at 0 degrees latitude. Each line is spaced evenly, with the North Pole at 90 degrees north and the South Pole at 90 degrees south. These lines help in navigation and mapping by providing a coordinate system. For example, the Tropic of Cancer is located at 23.5 degrees north, while the Tropic of Capricorn is at 23.5 degrees south. Latitude lines are essential for understanding climate zones and geographical features.