Tuscany is always busy with tourists and Umbria is steadily gaining in popularity, but their neighbor to the east—Le Marche—is still somewhat under the radar.
Le Marche (sometimes called simply “Marche”) is just east of Umbria and between Emilia-Romagna to the north and Abruzzo to the south. The part along the Adriatic Sea is relatively flat and dotted with beach towns, but otherwise it's a hilly and even mountainous region. The Apennine Mountains form the western regional border, and the foothills slope down from there toward the coast.
The only UNESCO site in Le Marche is the historic city center of Urbino, with many buildings dating from the 15th century. The region's beaches get crowded with vacationing Italians (and often other Europeans) during the summer months, and the many hills are a major draw for outdoor activities like hiking and mountain biking.
Le Marche's capital city of Ancona is reachable via the Italian rail network, but the vast majority of the region—including the UNESCO city of Urbino—is difficult or impossible to navigate by train. There is a rail line running down the coast, the only real flat land in the region, and otherwise your best bet to get around Le Marche is to have a rental car—not to mention a strong stomach for twisting mountain roads.
Photo credits: pavel068