The Tropic of Cancer is located at 23.5 degrees north latitude. It marks the northernmost boundary where the Sun is directly overhead and serves as the dividing line between the subtropical and tropical zones. The Tropic of Cancer monument in Jinpu is situated at the 69 km mark along Highway 11. On the summer solstice each year, the Sun rises in the east and sets in the west along the white tower's path. As such, the tower's design includes a narrow gap for observing this phenomenon. At around noon on the summer solstice, sunlight perfectly aligns into the gap. At that moment, visitors standing near the tower can experience the shadowless wonder produced by the Sun's position.