Summer Sun Celebration

Summer Sun Celebration is an event marking the day of summer solstice, which is also the longest day of the year.

The celebration is held from the night before to at least the dawn. The festival also marks the day Nightmare Moon was predicted to escape her banishment to the moon, and the first episode takes place during the thousandth year of the event, when Nightmare Moon succeeds in freeing herself and returning to Equestria. Parties are held all night long to witness Princess Celestia raise the sun of the summer solstice. One of Twilight Sparkle's flashbacks during The Cutie Mark Chronicles shows her witnessing such a sunrise.