Card 3: Catacombs is the 3rd Card of The 39 Clues. It comes with The Maze of Bones. Although the card states that it is a puzzle, the 39 Clues website does not have a puzzle tab for this card.
"As you know, Ben Franklin hid a vial in the St-Pierre de Montmarte church in Paris. What you don't know is that he also hid a Clue in another part of the Catacombs. The maze above shows exactly where Franklin's Clue is hidden."
The code for this card, along with the other cards in the Maze of Bones set, is '2D9TMDCPX2'
This card, combined with Card 1, Card 2, Card 4, Card 5, and Card 6, forms the Clue Iron Solute.