The Battle of the Labyrinth camp for the school year. On his fifteenth birthday at the summer's end, Percy receives a visit from his father Poseidon, who gives him a sand dollar, admonishing him to “spend it wisely”. Nico later appears to tell Percy his plan to defeat Luke once and for all. "The Battle of the Labyrinth" was initially referred to as "Percy 4" until the title was officially revealed. The novel was teased by Rick Riordan behind the pages of its predecessor, "The Titan's Curse". It was based on the Greek myth of the labyrinth, where the Minotaur was supposedly kept. In his
MIT Daedalus aircraft suffered damage to the right wing, fuselage, and propeller. "Daedalus 87" was repaired and returned to service to act as a backup airplane to "Daedalus 88". "Daedalus 87" was on display in the lobby at the Museum of Science, Boston until 2009, and is now on display above the tram stop for Terminal B at Dulles Airport outside Washington, DC. The final aircraft in the MIT Daedalus series, "Daedalus 88", was used in the flight from Crete. Pieces of "Daedalus 88" are now in storage at the Smithsonian's restoration facility. Both Daedalus aircraft were constructed with a framework of