A few miles off of the Mexican Coast of Puerto Vallarta lie the uninhabited Marieta Islands, It looks like something out of a fantasy novel: a wide, sandy cavern with the blue waters of the Pacific rushing in. The islands are an archipelago, a chain of land formations formed many thousands of years ago by underwater volcano eruptions. The interior limestone layer of the rock eroded over time, due to acids in rainwater from the surface seeping into fractures and dissolving it. This created a small cave, leaving a sturdier exterior shell that was less susceptible to decay. As the cave grew in size, the roof was unable to support its own weight and collapsed. Through an opening, waves washed out debris and brought in sand until finally the beach was formed. They themselves are natural wonders, but it was something other than volcanic activity that brought the burrowed beach to light
It is rumored that the hole that created the Hidden Beach was a result of deliberate bombings. The Marieta Islands have always been completely uninhabited, making them ideal sites for military testing by the Mexican government. Beginning in the early 1900s, weapons and artillery were tested on the Marieta Islands, a safe distance from Mexican citizens but not so safe for Marieta topography. Test bombs are the known cause for many caves and rock formations on the island, possibly including the Hidden Beach. Today one island in particular, Isla Redonda, is home to a beautiful geological feature: the “Playa del amor” or “Beach of Love” - an underground, donut-shaped beach carved into the rock.