40 years ago today, on October 10, 1985 (August 26, 1985 in the lunar calendar), the remains of ancient Indian dials were discovered. Archaeologists recently restored a huge ancient Indian sundial in a river valley in southwestern Illinois. This is a circle with a diameter of 136 meters surrounded by forty six-meter-high fir trees. According to textual research, the Kehekya Indians who lived in this area between 900 and 1100 AD used it to distinguish the summer solstice, winter solstice, vernal equinox, and autumnal equinox, and determine important dates in the Kehekya calendar. This ancient sundial site was discovered as early as 1961, but at that time archaeologists found only some deep pits for tree trunks. Later, an archaeologist named Warren Wittley saw that the pits were evenly distributed and realized that they were ancient sundial relics.