The Museo di Roma has a vast collection dedicated to the history of the city from the Middle Ages to the early twentieth century. Only part of this assortment of drawings, paintings, sculptures, frescoes, costumes etc. is on display at any one time. Palazzo Braschi itself is a solid and elegant palace dating to the eighteenth century, with a grand staircase boasting red granite columns once belonging to Caligula. The building's original frescoes can still be seen in many of the rooms of the museum.

Some of the most interesting exhibits are the large scenic paintings of Rome, showing grand events. The artists have carefully included hundreds of small details of the crowd: the nobles in their carriages, the cardinals in all their finery, the youths who may be about to pick the pocket of a distracted gentleman.