Number Grid

<spoiler>

You can solve the puzzle by clicking in the following order 4-2-2-3-4-2-4 and reaching the goal reveals the following letters: C O N T E S T.

Poseidon's picture is in the San Fransisco projection [1]. Athena and Poseidon (god of the seas in Greek mythology) had a contest over who would be the patron deity of the city that would become Athens.

Answer: ATHENA

</spoiler>

Next book: History Lesson