Inside the palace are set up the Archaeological Museum, the Art Gallery, and the Gallery of Contemporary Art.

Palazzo Pianetti, a significant example of eighteenth-century architecture, was commissioned by the noble Pianetti family in the mid-1700s. The palace acquired its current appearance in the mid-nineteenth century when it was renovated on the occasion of Vincenzo Pianetti's marriage to a descendant of the prestigious Marche family Azzolino. In the following years, due to serious financial problems, the Pianetti family was forced to sell the entire palace. In 1901, the building was purchased by the Tesei family, the last owners before the gradual and partial acquisition by the Municipality of Jesi.

Since 1981, the main floor of Palazzo Pianetti has been the seat of the Art Gallery. The main features of this floor are the famous Gallery of Stuccoes and the rooms decorated with the Stories of Aeneas, two of which house the well-known works by Lorenzo Lotto. The original core of the collection comes from works that became municipal property thanks to the Valerio decree, and was later expanded through donations. The rooms on the second floor, entirely decorated in nineteenth-century style, have been hosting since 2002 the Gallery of Contemporary Art, whose works come not only from acquisitions but also from the Rosa Papa Tamburi prize created by the Jesi artist Orfeo Tamburi, and from the 1981 exhibition "La Ruota del Lotto" through which contemporary artists have reinterpreted the masterpieces of Lorenzo Lotto. Since 2017, in the premises of the former Stables of Palazzo Pianetti, the Archaeological Museum is set up, containing artifacts from the territory, the Pasquarella-Spridgeon collection, and a group of Roman statues.