The mystery of what happened to the Mayan civilization has plagued experts for years.  Now, however, scientists believe that the Blue Hole of Belize may hold the key to discovering what happened to the Mayans so many centuries ago.

Beginning around 2,000 BC, Mayan culture endured until 800 AD and it is presumed to be one of the most advanced civilizations in the world.  Its pyramids, architecture, urban structures, agriculture, knowledge of astronomy, mathematics, advanced hieroglyphic writing and famous calendar have matched many of the achievements of the other great civilizations of antiquity in Egypt, Greece, Mesopotamia, the Indus valley and China.  And as many of these contributions endure to this day, they are a testament to this once powerful civilization's greatness.

At its peak, the Mayan civilization included 19 million people and its influence was felt over 1,000 km from its central regions, stretching as far as Honduras, Belize, Guatemala, El Salvador and central Mexico. However, after 700 AD it began a gradual descent into disorder; however, why this occurred has remained a mystery to scientists of today. Now, a new study of minerals in the lagoons of Belize's Blue Hole confirms that not one, but two catastrophic and prolonged droughts, lasting for more than one hundred years, likely led to the breakup of this once powerful civilization.

The first drought occurred between 800 AD and 1,000 AD, forcing the Mayans north in search of water.  However, they were again hit with another long drought during the Little Ice Age, after 1,000 AD.  The second drought proved to be the nail in the coffin for the civilization.

While these theories are not new, the quantifiable data found by the new study irrefutably provides evidence to this end.  In 2012, scientists discovered a 2,000-year-old stalagmite that pointed to a major reduction in rainfall.  However, scientists have now broadened their search to include the sediments in the Blue Hole of Belize. 

"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 André Droxler, an Earth scientist at Rice University, says, "It's like a big bucket. It's a sediment trap."

"The main driver of this drought" says Live Science "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. 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."

Their crops failed and trade profits began to dry up, both leading to social unrest and internal disintegration of their civilization. 

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

Even so, the influence of the Mayan culture managed to continue even after the drastic fall of the civilization, as individual city states for a few centuries.  It took the Spanish conquistadors 170 years to finally put to rest all that remained of the Mayan civilization, though their social customs and legacy lives onto today.