Over the past Millenia, civilizations even before the age of written history, have fallen when faced with famine, disease and even war. But when the most advanced civilization in the world disappears without a reason, the mystery creates some unique speculations. For years now, researchers and archaeologists have sought out an answer to what happened to the Mesoamerican Mayacivilization, and while theories have run the gamut from mass suicide to disease and famine, researchers now believe that they have found the answer entombed in an underwater lagoon.

While the irony does not escape the researchers put to the task, in a new study conducted by researchers at Rice University say that in the underwater caves and surrounding lagoons of the Blue Hole in Belize lies evidence that the Maya civilization fell on account of not one, but two prolonged periods of drought lasting over 100 years.

"During storms or wetter periods, excess water runs off from rivers and streams, overtops the retaining walls, and is deposited in a thin layer at the top of the lagoon. From there, all the sediments from these streams settle to the bottom of the lagoon, piling on top of each other and leaving a chronological record of the historical climate" study's co-author, an Earth scientist at Rice University, André Droxler says, "It's like a big bucket; It's a sediment trap."

Using this sediment, which documents trace evidence for thousands of years, the researchers believe that coinciding with a 2012 study of a 2000-year-old stalagmite, the Maya civilization likely fell on account of a severe reduction in rainfall.

Beginning in 2,000 BC, Mayan culture has been documented in its pyramids, agricultural practices, knowledge of astronomy and famous calendar, which stands true through today, as one of the most advanced civilizations of ancient history. Enduring until 800 AD, the civilization in its peak included over 19 million people and spanned the regions of Honduras, Belize, Guatemala, El Salvador, and even as far north as central Mexico. But evidence revealed in the trace minerals of Belize's Blue Hole confirm that the once great civilization was not only displaced, but killed off courtesy of two concurrent droughts lasting more than 100 years.

"The main driver of this drought is thought to have been a shift in the intertropical convergence zone (ITCZ), a weather system that generally dumps water on tropical regions of the world while drying out the subtropics" researchers with LiveScience say. "During summers, the ITCZ pelts the Yucatan peninsula with rain, but the system travels farther south in the winter. [Therefore], many scientists have suggested that during the Mayan decline, this monsoon system may have missed the Yucatan peninsula altogether."

Though the drought alone may not have caused the entire civilization to have disappeared, the researchers believe that the major droughts exacerbated underlying issues causing the end of the Mayans altogether.

"When you have major droughts" Droxler says, "you start to get famines and unrest."

Yet, in spite of their end coming by way of the loss of vital waters, Mayan culture continues to influence Pan-American nations today, and a history of their existence lies just below the waters, in the sand.