Why do the Arctic Circle and the Tropic of Cancer have names?

The Arctic Circle and the Tropic of Cancer are named based on their geographical significance and historical observations. The Arctic Circle marks the latitude above which the sun does not set during the summer solstice and does not rise during the winter solstice, reflecting extreme daylight variations. The Tropic of Cancer is named because it was once the point where the sun was directly overhead at noon during the summer solstice when the sun was in the constellation Cancer. These names reflect their connection to the Earth's axial tilt and the changing seasons.