Constanta Romania. Fine mansions and hotels were built in the 19th century when King Carol I decided to revive Constanta as a port and seaside resort. The third-largest city in Romania, it is now an important cultural and economic center.  Its historical monuments, ancient ruins, shops, and proximity to beach resorts make it the focal point for tourists. Open-air restaurants, nightclubs, and cabarets offer a wide variety of entertainment.