Gaeta is the most frequently visited town for me. On both of my visits to Italy I stayed nearby in Formia and took a bus from the station to the section of Gaeta that divides the ancient from the medeival
A view of Gaeta from S Francesco.
Gaeta is built on the peninsular which juts into the mediterranean and creates the gulf extending to Naples. My major interests are the 'old rocks' in various stages of ruin to be found in and around the area.
Favourite spots:
Munazio Planco's Mausoleum in Gaeta.
The first and major 'find' is that of the mausoleum of Lucius Monazio Planco, a consul of Rome at the time of Ceasar and Mark Antony, to do a bit of name dropping. His mausoleum, situated at the very top of Mount Orlando, is said to be the best preserved mausoleum in Italy. It is a huge structure that has had various uses since the original. Being on the highest spot in the area, made it particularly important during the war. Another mausoleum from around the same time has not fared as well in the preservation stakes and was closed to visitors on my last visit in 2001, deemed to be now dangerous to walk through. Sempronius Attratinus I believe was also a consul but I haven't been able to find out much about him, Planco's one is very interesting however and I am waiting to hear more details about his associations with Mark Anthony.
What's really great:
Serapo Beach taken from Mount Orlando
As a holiday destination it has much to offer too. The main beaches are often mentioned on the list of least polluted swimming areas, most years. Serapo is particularly lovely and in the peak season is choc-a-blok with tourists all jostling for a position for their umbrella and chairs in front of their hotel. Gaeta is a wonderful place and just far enough away from Rome to be a get-away from the city type, while being close enough to get into all of the action that Rome can offer at night.
Sights:
The famous castles of Gaeta
Walking up Mount Orlando to see the Munazio Planco's Mausoleum is an absolute must from my perspective. If you travel there in holiday time there is a bus that will take you to the top (well almost) for a very small charge. It will also pick you up from various spots along the way.
Split mountain and the Grotto are also places to stop at either on the way up or back. Do remember to be aware of siesta times for the last two spots because you will not be able to get in if you arrive at those times.
The views at the top are spectacular.
Other recommendations:
I would also do the walk up Attratinus hill to see this mausoleum too. If you go through the medieval section of town there are some wonderful laneways and markets to be seen on the way.