The five major lines of latitude, more commonly referred to as the five major circles of latitude, mark specific points on a globe or map of Earth. Four of the lines run parallel to the equator and sit north or south above or below the equator.

• The Arctic Circle is located at approximately 66.5 degrees north latitude, or 66.5 degrees north of the equator. This circle of latitude stretches through eight countries, including the United States, Canada, Greenland, Iceland, Norway, Sweden, Finland and Russia.
• The Antarctic Circle is located at approximately 66.5 degrees south Latitude, or 66.5 degrees south of the equator. This line, or circle, of latitude marks the start of the southern area known as the Antarctic. The circle consists of only one continent, Antarctica.
• The Equator or great circle is possibly the most well-known circle of latitude is the line sitting at zero degrees latitude, the equator. The equator circles the globe with a circumference of nearly 25,000 miles, dividing the northern and the southern hemispheres. This line of latitude is the starting point when referring to other points of the globe in terms of degrees north and degrees south.
• The Tropic of Cancer is located at approximately 23.5 degrees north latitude, or 23.5 degrees north of the Equator. This line of latitude is the northern boundary of the area referred to as the tropics. During the summer solstice the sun is located immediately above the Tropic of Cancer. This line is the point farthest to the north at which the sun is hanging directly upward at noon.
• The Tropic of Capricorn is located at approximately 23.5 degrees south Latitude, or 23.5 degrees south of the equator. This line of latitude is the southern boundary of the area referred to as the tropics. This line marks the point farthest to the south at which the sun is hanging directly upward at noon. During the summer solstice of the Southern Hemisphere, the sun is located immediately above the Tropic of Capricorn.

Source: ForumIAS