Tropic of Capricorn
Southern tropic, 23.4° S.

Tropic of Cancer
Northern tropic, 23.4° N.

Equator
An imaginary line equidistant from the north and south poles

Arctic Circle
Northern polar circle, 66.5° N.

Antarctic Circle
Southern polar circle, 66.5° S.

International Date Line
Any given day starts here and progresses west, with yesterday nipping at its heals