San Marino is a whole country balanced on the ridge of a single mountain, and you feel it the moment the road starts to climb out of the coastal plain. Monte Titano rises steeply from the hills behind Rimini, a long limestone crest with sheer cliffs on its eastern side, and the old town of San Marino clings to the top with three towers strung along the ridge like stitches. The first, Guaita, is the oldest and the most photographed; the second, Cesta, sits on the highest point; the third, Montale, is a slender lookout you can only see from outside.
Tradition says the republic was founded in 301 by Marinus, a Christian stonemason from the Dalmatian coast who fled persecution and settled on the mountain. Whatever the precise truth, San Marino claims to be the oldest surviving republic in the world, and it has kept its independence through popes, dukes, Napoleon and the unification of Italy. It is still governed by two Captains Regent who serve six-month terms, a system older than most of Europe's states.
The road up from Rimini runs through the lowland towns of Serravalle and Borgo Maggiore and then begins to switchback, with the Adriatic spreading out behind you and the coastline curving away toward Pesaro. It is a busy road in summer, full of coaches and cars, so pick your time: early in the morning or later in the afternoon you get the climb with fewer people and kinder light. There are car parks around the old town where bikes can be left; from Borgo Maggiore a cable car runs up to the centre.
The views from the top are the reason to come. On one side, the coast and the sea; on the other, the Montefeltro, a wild jumble of hills and rocky outcrops that rolls away toward the Apennines. The roads into that country, toward San Leo with its fortress on a cliff and on to Urbino, are wonderful, twisty and much quieter than the coast, and they are the natural continuation of the ride.
Fuel in San Marino has generally been a little cheaper than in Italy, thanks to different taxation, and stations line the main road through the lowlands; Borgo Maggiore and the other towns have shops and bars too. Up in the old town, try a slice of torta Tre Monti, a layered wafer cake named after the three towers, and enjoy the strange feeling of having crossed a border without noticing.