Catacombs of San Gennaro
Naples is called the "City of layers” with a 100 steps to the bottom layer. Relatives go down into the catacombs to “speak with the dead”. The lower catacombs are carved into stone, the burial site for the public and it welcomes visitors. The upper catacombs is where the bishops are buried. It's completely accessible for everyone with ramps, stairs, paved walkways, and metal plates to explain a significant attraction. Open Monday through Saturday from 10 am to 5 pm. Sundays and holiday from 10 am to 2 pm.
Teatro di San Carlo
Naples underground geothermal zone: or “Napoli Sotterranea” is located 40 feet beneath the streets of Naples, where you can see air raid shelters from WWII, and few of the tuffaceous cavities excavated in the Greek era. You are given a candle to walk with on the smooth walk underground. The tour lasts about an hour.
Tours in Italian: daily: 10 am - 6 pm every hour on the hour
Tours in English: 10 am, noon, 2 pm, 4 pm, 6 pm