Twelve kilometres northeast of Trinidad are three interconnected rural valleys – San Luis, Santa Rosa and Meyer – that make up the 225-km2 Valley de los Ingenios. More than fifty sugar mills were in operation here at the industry’s peak in the 19th century, and in 1827 more than 11,000 slaves were working in the mills.

A long, gradual decline in Cuba's sugar industry accelerated significantly in the 1990s. The former plantations, mill buildings and other facilities and archaeological sites in the Valley de los Ingenios represent the richest and best-preserved testimony of the Caribbean sugar agro-industrial process of the 18th and 19th centuries, and of the slavery phenomenon associated with it.

In 1988, Valle de los Ingenios and neighbouring Trinidad were declared a World Heritage Site by UNESCO. Although most of the sugar mills are in ruins, intact structures endure at some sites, including Guachinango, where the plantation house remains, and the plantation of Manaca Iznaga, where the owner's house, a tower and some barracones, the original slave quarters, still stand. Although the barracones are now used as housing and are in poor repair, the house (which has been converted into a restaurant) and the "Iznaga Tower" are well maintained. The 45 metre  tower was constructed sometime in 1816 by the owner, Alejo Maria Iznaga y Borrell.

According to experts, the bell that formerly hung on top of the tower announced the beginning and the end of the work day for the slaves, as well as the times for prayers to the Holy Virgin in the morning, midday and afternoon. It was also used to sound an alarm in case of fire or slave escape. The height and magnificence of the tower served to display Iznaga's power over his slaves and his stature in the sugar industry and local society; at one time it was the tallest structure in Cuba. A recognised landmark of the region, the Iznaga Tower testifies to the area's flourishing material culture in the Spanish colonial period. The large bell now rests at the foot of the tower.