1. Teeth
2. The doctor is the boy's mother
3. Alucard spelled backwards is "Dracula"
4. The Path to Illumination. The riddle tells Robert Langdon that he must follow the Path to Illumination, something every Illuminati member follows, in order to save the Catholic Church.
5. A stampede
6. Depends. African or European?
7. This refers to the Declaration Of Independence
8. A match
9. Leonardo da Vinci, The Mona Lisa
10. They weigh the same: nothing. U.S. currency isn't printed on paper from trees, and trains go through Grand Central Terminal, not Station.
11. The moon
12. Mellon. It's the Elven word for "friend."
13. Take the sheep over, come back alone, take the cabbage over, return with the sheep, take the wolf over, come back alone and take the sheep over.
14. There isn't an answer. The Mad Hatter is mad.
15. Just one. The narrator.
16. Ask either guard which door the other guard would say leads out. To stay alive, you must walk through the opposite door you’ve been told to use.
17. A ring. Specifically, the ring of the Lord of the Marsh, Calibos, which features two perfect pearls and a circle of gold.
18. Bats
19. Vowels ("a tennis court" features A-E-I-O and U)
20. A mountain
21. Spiders
22. A clock
23. Dark
24. Chess Pawns
25. Time
image courtesy of AZMIL via Shutterstock