Chanukah celebrates the victory of the Jews over the Syrian-Greek armies.
When the victorious Jews entered the Holy Temple, they found enough pure oil to light the menorah for one day, yet it lasted 8 days until new oil was brought. Today, we light the Chanukah menorah to remember the miracles that G-d performed.

Chanukah teaches us that just like the Jews found a small jar of pure oil hidden in the Temple, each of us has a pure spark of holiness hidden in our hearts. This spark can never be defiled or destroyed!