Colonia, founded by the Portuguese in the 17^th century under the command of Maestre de Campo Manuel de Lobo, bears a strong resemblance to Old World Europe—more so than any Spanish colonial city found in Uruguay or Argentina. Colonia's mixed Spanish and Portuguese architecture reflects the city's turbulent past, constantly changing hands between the two colonial powers as they fought to secure the limits of their empires. This history led UNESCO to declare the city a world heritage site in 1995. 
Colonia exhibits some of Uruguay’s oldest buildings: El Convento de San Francisco Javier, built between 1683 to 1704, is particularly interesting architecturally. On Calle Vasconcellos, La Iglesia Matriz was the first church to be built in Uruguay.
Under Portuguese control in the early 18th century, Colonia became a major point of trade for Portuguese and British contraband. The then King of Spain, Felipe V, reacted by ordering that Montevideo be built up in order to keep an eye on smuggling in Colonia. After many disputes and hand-offs between the Spanish and the Portuguese, governance of the city became a joint responsibility of Buenos Aires and Montevideo in 1777.
Uruguay's one and only bull ring, or Plaza de Toros, is located in Colonia.  The amphitheater was constructed just two years before bullfighting was outlawed in the country in 1912.