In this third chapter book starring Rafi and Rosi, the two tree frog siblings explore their island home of Puerto Rico and learn about its Spanish history, fortresses, and pirates. In this new book in the popular Dive Into Reading: Rafi and Rosi chapter book series, Rafi and his younger sister, Rosi, are excited to visit El Morro Fort, the four-hundred-year-old fortress that guards the entrance to San Juan harbor. At the fort they pretend to be pirates, engage in a fierce battle, and learn about Roberto Cofresi, Puerto Rico's most famous pirate. As they go deeper into the fort they discover a gleaming, hidden treasure--Spanish gold doubloons and silver pieces of eight--hidden in the inner reaches of the fort's kitchen. After turning over their discovery to the fort's museum, Rafi is ready to go back to Tia Ana's home, but Rosi wants to play hide-and-seek. And Rosi sees the perfect place to hide--in the stone sentry box that once housed the fort's lookout guards. Little does she know that the sentry box might be haunted! Engaging and informative, the book is perfect for independent readers in grades 1 and 2. Children will enjoy joining Rafi and Rosi on their new adventures while they learn about Puerto Rico's history.