Holy Trinity Church on Plaza Mayor, is the focal point of the Trinidad. This church took from 1817 to 1892 to complete and is the largest church in Cuba. I bet there was not even one church build under Castro. I've seen few closed or converted for secular use.
The inside of the church looks like a poor cousin to the churches of Europe. It feels empty, only few old people come to pray.
Trinidad was declared by UNESCO World Heritage Site in 1988, along with the Valle de los Ingenios. In 1790 there were 56 sugar mills operating and 12,000 slaves working in the sugar cane fields. Today, there is very little sugar cane in this area of Cuba.