After Karnak, the Temple of Horus is the largest temple in Egypt. It is also the best preserved, as it was almost completely buried in sand until the 1860s. The temple was built on the site where Horus was said to have fought w/ his evil Uncle Seth to avenge his father's death & gain control of the world. Here you'll see the entire story in deep-carved reliefs telling how the evil Seth trapped Osiris in a coffin & threw him into the Nile. Of how Isis found Osiris' body & was able to revive him long enough to conceive their son, Horus. How Seth took Osiris' body, cut it into 14 pieces & threw it back into the Nile. Isis was able to gather 13 pieces, but never recovered his penis, which was eaten by a fish & Horus grew up to avenge his father's death.
It's a powerful tale of good vs. evil & good prevailing. Still today, it carries w/ it "superstitions" (for lack of another word), such as the #13 being unlucky for the 13 found pieces of Osiris, not eating a certain kind of fish that ate Osiris' penis, & wearing black to mourn Osiris.