They're not invisible on maps, but the don't exist on the earth's surface.
equator- zero degree latitude prime meridian- zero degree longitude arctic circle- the sun does not appear in northern solstice antarctic circle- the sun does not appear in southern solstice tropic of cancer tropic of Capricorn international dateline-the back of the prime meridian latitude-the horizontal lines longitude- the vertical lines
The imaginary line 23.5 degrees north of the equator is called the Tropic of Cancer.
Only the Prime meridian determines time. The International Date Line determines days because it is a separator of Day 1 and Day 2. The equator, Tropic of Cancer, Tropic of Capricorn, Arctic Circle and Antarctic Circle determine different regions on Earth that have different climates.
The Prime Meridian is the invisible line at zero longitude
the Prime Meridian
The Tropic of Capricorn is a parallel of latitude. Every meridian of longitude intersects it perpendicularly.
The Prime Meridian is a invisible line which runs from the north pole to the south pole.
Meridian
Africa.
Africa
The Tropic of Capricorn crosses every meridian of longitude on the face of the earth, but no latitudes.
The southernmost land crossed by the Prime Meridian is the Antarctic continent, but there are no countries there. The southernmost country on the Prime Meridian is Ghana.