The festival that celebrates the arrival of spring and new beginnings in ancient Persia is called Nowruz. This celebration, observed on the vernal equinox, marks the start of the Persian New Year and symbolizes rejuvenation and renewal. Traditional activities include family gatherings, feasting on special foods, and various customs like the Haft-Seen table display, which includes seven symbolic items starting with the Persian letter "S" to represent health, wealth, and prosperity.