The term Capitol Feature refers to the architectural features of a capitol building, which typically includes a CUPOLA, PORTICO, DOME, and rotunda. A CUPOLA is a small, DOME-like structure on top of a roof, often used for ventilation or decoration. A PORTICO is a porch-like structure with a roof supported by columns. A DOME is a curved, hemispherical structure that covers a building, often used as a roof. Finally, a rotunda is a circular room with a DOME-shaped roof, often used as an entrance hall.