The Plaza Mayor is the city's historic center, declared a UNESCO World Heritage Site in 1988. The buildings that surround it date back to the 18th and 19th centuries, when the trade of sugar from the nearby Valle de los Ingenio, taking advantage of slave labor ,brought great wealth to the area. Many of these buildings surrounding the square belonged to the wealthy landowners of the city.
When the trade of sugar decreased and the slave trade ended in the mid-19th century, Trinidad became "stagnation" and little construction work, this until 1950. As a result, many of the historic buildings and streets have been preserved, especially the large colonial buildings in the immediate vicinity of the Plaza Mayor. Today most of the houses surrounding the square, have been turned into museums.