1. Time
   1. on 31 October
2. origination
   1. From ancient Celtic harvest festivals
3. Symbols
   1. imagery
      1. Pumpkins
      2. Ghosts
      3. witches
      4. owls
      5. zombies
      6. bats
      7. ...
   2. Theme
      1. death
      2. evil
      3. mythical monsters
   3. Color
      1. Black
      2. orange
      3. purple
4. Trick or treat?
   1. Customary celebration for children
   2. Treats
      1. Candy
      2. Sometimes money
5. Costumes
   1. Supernatural figures
      1. vampires
      2. monsters
      3. ghosts
      4. skeletons
      5. witches
      6. devils
   2. Popular characters
      1. ninjas
      2. princesses
   3. The first mass-produced Halloween costumes
      1. in the 1930s
6. Games and other activities
   1. Apple bobbing or dunking
   2. Foretelling one's future partner or spouse
   3. Telling ghost stories
   4. Watching horror films
7. Food
   1. Candy apples
   2. Caramel apples
   3. Halloween cake
   4. Roasted sweet corn
   5. Bonfire toffee
   6. ...