Colonia del Sacramento is a city in southwestern Uruguay, by the Río de la Plata, facing Buenos Aires, Argentina. It is one of the oldest towns in Uruguay and the capital of the Colonia Department. It has a population of around 27,000.
Its historic quarter is a UNESCO World Heritage Site. Modern Colonia del Sacramento produces textiles and has a free trade zone, in addition to a polytechnic centre and various government buildings.
Wikipedia https://en.wikipedia.org/wiki/Colonia_del_Sacramento
More information on whc.unesco.org http://whc.unesco.org/en/list/747
Address 101 Calle de La Playa, Colonia Del Sacramento, Uruguay
Coordinates -34°28'17.792" N -57°51'6.728" E