Possible Clues:

• South Temperate Zone border
• Geographic area around the South Pole
• Wrong right in two acts with line — one round pole
• About 66 degrees south latitude
• Line of latitude north of the South Pole
• Earth's southernmost latitude
• You must be under this to see The Longest Day
• It's between the South Frigid Zone and South Temperate Zone
• Southern Hemisphere imaginary line
• Emperor penguin's realm