The seventh day of the seventh lunar month is Qixi, widely regarded as China's Valentine's Day.
Legend has it that the youngest daughter of the Jade Emperor (the ruler of the world as per the legend), the Weaver Girl, became tired of the boring immortal life and decided to descend to the mortal world. She met and fell in love with a cowherd, a union strongly objected by the Jade Emperor who in turn forcibly separated them by the Milky Way, leaving them torn apart by the galaxy and only allowing them to meet once a year, on the seventh day of the seventh lunar month.
The distance did not weaken their affection toward one another, as they still loved each other and looked forward to meeting once a year on the seventh day of the seventh lunar month.