During my most recent visit to Italy (May 2016), I had one free day to go exploring. Portovenere is known as the town that is like the sixth town of Cinque Terre. It has all of the charm of the famous five towns, but it is more difficult to reach. One can get there by car, bus, or boat (but not a train). If your eyes are young, you can see it from Lerici and much of the year the boat to Cinque Terre stops in Portovenere.
There is a commanding fort and church high above the town.
“The ancient Portus Veneris is believed to date back to at least the middle of the 1st century BC. It has been said that the name refers to a temple to the goddess Venus which was sited on the promontory where the church of Peter the Apostle now stands. In Roman times the city was essentially a fishing community.
After the fall of the Western Roman Empire, Porto Venere became the base of the Byzantine fleet in the northern Tyrrhenian Sea, but was destroyed by the Lombards in 643 AD. First indications of the existence of a castle date from 1113, and in 1161 the walls were erected.” Wikipedia