Palazzo Altieri, the symbolic building of Oriolo Romano, in front of which stands the beautiful Fountain of Spades, attributed to Jacopo Barozzi da Vignola, belonged to the Santacroce family from 1578 to 1604 and has the typical features of 16th-17th century fortress-dwellings: surrounded by a moat, it rises four storeys high and is protected by two corner bastions from which the two rear wings start, giving the building a U-shaped layout. In the palace, the garden of about 8 hectares, now owned by the municipality, is worth visiting and can be reached by a small bridge. The garden is reached by a small bridge and contains centuries-old trees such as yews, silver firs, holm oaks, Turkey oaks and a monumental yew tree that is over 100 years old. Inside the Palazzo, which is part of the Polo Museale del Lazio, the various rooms contain galleries of fine paintings, including the Galleria dei Papi, stucco and neoclassical furnishings and frescoes.
The Villa is an urban park of 8 hectares completely accessible and with an important presence of monumental trees. A fountain and a hunting lodge complete the park.