Somewhere between Terracina and Formia, you'll find it. There's a stark pillar along the side of a winding mountain road. I assume it's either a milestone or the remains of one of the many monuments that line the Appian way.
The bike ride to this pillar is phenomenal, and there are at least three good reasons to make the trip. First is the "Tomb of Cicero" at one end of the bike route. Most experts agree that this isn't the really the tomb of Cicero, but it's near the spot where he died and that's enough for most people.
Better than Cicero's tomb, the bike ride from Terracina to Formia passes through a park which includes the original remains of the via Appia, as well as several ancient Roman and Medieval buildings.
In fact, if you're riding your bike on the main road, you'll pass through the park several times. The road winds up the mountain in endless switchbacks, while the Appian Way shoots up in the classical straight line, defying gravity just as easily as she defied the Pontine marshes. You can ride your bike up this way if you choose to. I didnt.
But my favorite thing about this section of the Appian bike tour is the town of Itri. I hadn't meant to stay there, but I was intrigued by the scenery, the friendly locals, and the castle. After taking a long hot shower and stuffing my gullet with fresh pizza, I spent hours wandering around the dark, twisting alleys of the immense fortress on the hill overlooking Itri.
I can't tell you much about the history of the castle, but I'll introduce you to someone who can. On our next bike tour through southern Italy, one of my local contacts has offered to hook us up with an archeologist in Itri who can give a tour of the place. I asked him how much something like that would cost and he said, "some cafe in a bar, I assume, but not more..."
So if you're up for an expert tour of Itri for the price of a cup of coffee, not to mention a zillion other great experiences that you can read about all over my blog, get in touch with me and join us on this trip. The dates are May 15th-June 1st 2010, approximate cost is $1500 plus airfare and bike (rental, purchase, or transportation of your own rig), and I'll be happy to answer your other questions by phone or email.