“We have to preserve what we have of our Puerto Rican identity,” says Iraida Rodríguez-Negrón, a curator at Puerto Rico’s Museo de Arte de Ponce. That’s why her institution is loaning 21 important paintings to Chicago’s National Museum of Puerto Rican Arts and Culture for the exhibition Nostalgia for My Island, opening September 20. Chosen to embody Puerto Rico’s spirit, the pieces include works by José Campeche and Francisco Oller, among the island’s most celebrated artists. It’s the first time most of these paintings, which date from 1786 to 1962, have been shown outside Puerto Rico. The free exhibition is organized into three parts: one featuring countryside and city scenes; another exploring identity and traditions; and the third displaying the splendor of Puerto Rico’s nature and food. 3015 W. Division St.