"Castel Nuovo" was constructed in 1279-1282 for Charles I dAnjou and since then it has been modified several times. The facade is a 15th century work. This is a must see monument in Naples, because between the entrances towers theres the Alfonso I Triumph Arch, the most important Renaissance work in Naples. This Arch commemorates Alfonso I of Aragon and Naples arrival to the city back in 1443. Inside this castle you can visit the "Museo Civico" (with Napolitan history paintings), the Palatine Chapel and the "Sala dei Baroni".
Well now take the "Funiculare Centrale".