Mexico's Natural Monuments (or Monumentos Naturales in Spanish) are four federally recognized protected natural areas that are administrated by the federal National Commission of Protected Natural Areas (CONANP).
CONANP defines Natural Monuments as areas that contain one or more natural elements, that have a unique character, aesthetic, historic, or scientific value, that require absolute protection. Sites do not need to have a variety of ecosystems to be included in this category.
List of Sites
The four sites are:
References
Mexican Natural Monuments Wikipedia(Text) CC BY-SA