The Malatesta Seignory in the Marecchia Valley consists of  4 Comuni (municipalities):

SANTARCANGELO di Romagna
VERUCCHIO
POGGIO BERNI
TORRIANA / MONTEBELLO
all very rich in history and monuments.
The towers and castles in the Marecchia Valley, including Saiano, San Leo and San Marino, all share one very noticeable feature: they all stand on harsh rocky outcrops high above the countryside and offer beautiful views in all directions, towards both the mountains and the sea. The Malatesta Seignory found here its first and fundamental power base between the Middle ages and the Renaissance.

Worth seeing:

Santarcangelo
Cervese Gate (Porta Cervese)
Ganganelli Arch (Arco Ganganelli)
Piazza delle Monache e Piazzetta Galassi
Malatesta Fortress
"Del Campanone" tower
Collegiate Church (Chiesa Collegiata)
Parish of Saint Michael Archangel (Chiesa di San Michele Arcangelo)
Ethnografic Museum of the Uses and Habits of the People of Romagna
Mangano (Old cloth printing workshop)
Sferisterio (Ball Court)
Piazza Monache and via Ruggeri caves
Musas - Archaeological History Museum
Convento dei Cappuccini sec. XVII - XIX (can only be visited externally)

Verucchio
Malatesta Fortress
Villanovian Municipal Archaeological Museum
Passerello Fortess and Gate
Collegiate Church (Chiesa Collegiata)
Ancient Spring and Malatesta Well
Piazza Malatesta
Franciscan monastery and Holy Cross church
Romanesque Church
Moat walls
Old town centre

Poggio Berni
Moroni Mill
Marcosanti Palace
Astolfi Palace
Cava Querry Park
Parish church of Sant'Andrea
Church of Santa Maria Annunziata in Camerano
Church of Santo Marino
Tonino Guerra's "Memory's fountain"

Torriana - Montebello
Sanctuary of the Madonna of Saiano
Torriana Tower
Malatesta Fortress
Fortress of the Guidi of Bagno Family
The Water Tree