On the east bank of the Río de la Plata, 112 miles (180km) west of Montevideo, but only 31 miles (50km) from Buenos Aires by ferry, Colonia is an irresistibly picturesque town enshrined as a Unesco World Heritage site. Its Barrio Histórico, an irregular colonial-era nucleus of narrow cobbled streets, occupies a small peninsula jutting into the river. Pretty rows of sycamores offer protection from the summer heat, and the riverfront is a venue for spectacular sunsets (it's a Uruguayan custom to applaud the setting sun). Colonia’s charm and its proximity to Buenos Aires draw thousands of Argentine visitors; on weekends, especially in summer, prices rise and it can be difficult to find a room.