Colonia del Sacramento

Colonia del Sacramento needs 2 days: the Barrio Histórico, with 17th-century Portuguese-origin cobblestone streets and the Colonia Lighthouse, on one, a walk along the Calle de los Suspiros, the country's most photographed street, on the other. September-April is best. It's mid-priced, with boutique lodging geared toward weekend tourism from Buenos Aires, just 1 hour away by ferry. It was founded by Portugal in 1680 as a strategic outpost facing then-Spanish Buenos Aires, and its Historic Quarter, with architecture blending Portuguese and Spanish features, has been a UNESCO World Heritage Site since 1995.