These basaltic prisms located in San Miguel Regla are the unique ones in the whole American continent. These Basaltic Prisms are made of igneous rock, known as prismatic basalt, formed into a fifty meters high vertical wall of gigantic columns, decorating the walls of a gully known as Alcholoya. These basaltic prisms were formed by the accelerated cooling of lava millions of years ago. They are at the waterfall formed by the San Antonio Dam, which falls through the prisms and into the river. Especially for tourists, who visit this incredible place, hanging bridges and paths were constructed.
Near the basaltic prisms, there are two marvelous haciendas – Santa Maria Regla and San Miguel Regla. These Haciendas are considered to be one of the biggest in the world. They were created in the years 1760 – 1780 by the Spanish Pedro Romero de Terrenos. He was born in 1710 in Spain and died in 1781 in San Miguel Regla. He was one of the major producers of silver in New Spain. These haciendas were the first ones where gold and silver were produced. In the 20th century a new stage in the existence of the Haciendas began: they turned into the posh hotels.