The Tropic of Cancer is the circle of latitude that is 23.5 degrees north of the equator and the northernmost point where the sun appears directly overhead at the summer solstice. There are a few synonyms for the Tropic of Cancer, including the northern tropic and the parallel of latitude that runs through Mexico, The Bahamas, Mauritania, Mali, Niger, Algeria, Libya, Egypt, Saudi Arabia, United Arab Emirates, Oman, India, Bangladesh, Myanmar, and China. This imaginary line played a vital role in ancient astronomy and navigation, and it continues to be an important reference point today, especially in the study of climate and the Earth's seasons.