The total population is recorded as 8,753 (4,281 males, 4,472 females in 3,753 families), the population density (per square kilometre) as 193.8, and number of housing units as 3,983.
The two castles are the main attraction. The older castle, dating back to the eleventh century, is in ruins, while the newer castle is inhabited to this day and can be visited by tourists.
Below the ruins of the ancient castle there lies a white rock projecting into the sea, the Dama Bianca, which resembles a veiled woman and gave origin to many gothic legends.
The new castle of Duino is approximately dated to about the year 1400, when the family Wallsee commanded the construction of a strong fortress. Over time, the Wallsee family disappeared and the castle, after having been used as a prison, became the residence of the Luogar and Hofer. At the end of the 19th century it became the property of Prince Alexander Johann Vincenz Rudolf Hugo Karl Lamoral Eligius von Thurn und Taxis from the Czech Branch of the House of Thurn und Taxis. It remains with the family to this day with his great-grandson Prince Carlo Alessandro della Torre e Tasso, Duke of Castel Duino the current owner. The castle has been opened to the public as a museum and park.
Since 1982 the town has been home to the United World College of the Adriatic, a no-fee international school attended by students from 80 different countries.