Birthplace of the Argentine flag as well as two of the nation's most famous exports, Che Guevara and Lionel Messi, Rosario is still an important river port but has done a great job of regenerating its center. The derelict buildings of the long costanera have been converted into galleries, restaurants and skate parks, and river beaches and islands buzz with life in summer. The center – a curious mishmash of stunning early-20th-century buildings overshadowed by ugly apartments – has a comfortable, lived-in feel, and the down-to-earth rosarinos (people from Rosario) are a delight.