Naples' Palazzo Reale (Royal Palace) is home to the Biblioteca Nazionale, its priceless treasures including at least 2000 papyri discovered at Herculaneum and fragments of a 5th-century Coptic Bible. You will need to email the library a month ahead to organise a viewing of the papyri. If you're not that organised, head in regardless to view its beautiful 2nd-floor Biblioteca Lucchesi Palli (Lucchesi Palli Library), designed by some of Naples' most celebrated 19th-century craftspeople.
The Sezione Lucchesi Palli is home to numerous fascinating artistic artefacts, including letters by composer Giuseppe Verdi. If the door to the Sezione Lucchesi Palli is closed, simply ring the buzzer by the door. Note that photo ID is required to enter the Biblioteca Nazionale.