The Cathedral of the Sea by Ildefonso Falcones

The Cathedral of the Sea is a historical novel by Spanish author Ildefonso Falcones. The book tells the story of Arnau Estanyol, a young boy from Barcelona's poor neighborhoods who fights for survival in 14th-century Spain. Arnau lands in a mysterious world where he encounters love, friendship, and hostility. The book became a bestseller and has been translated into over 35 languages.