Ruins of the ancient Mayan city of Calakmul surrounded by the jungle, Campeche, Mexico
© Alfredo Matus/Shutterstoc
A lost civilisation
This massive pyramid temple, known simply as Structure 2, lay undiscovered for centuries, buried deep in the jungle of southern Mexico. It is the largest structure of thousands discovered in the Classical Mayan city of Calakmul, which, 1,200 years ago, was home to about 50,000 people. The ruins of the city cover nearly eight square miles in the jungle and the wider kingdom, which at its peak numbered more than 1.5 million people, once ruled over settlements up to 90 miles away. Yet it was lost to history until December 1931 when an American botanist spotted it as he flew over, on a survey of the jungle. A few expeditions were sent to explore it over the next few years, but it went largely unstudied until the 1980s. Now Calakmul is recognised as one of the most important archaeological sites in southern Mexico.