The Pyramid of the Sun in Mexico
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Mexico's famous Pyramid of the Sun 'at risk of sinking'

10 April 2014 Last updated at 20:05 BST

A team of researchers in Mexico has warned that one of the country's top tourist attractions - the Pyramid of the Sun - could be slowly sinking into the ground.

Thought to be a fertility symbol built around 80 AD, the pyramid - which lies about 50 kms (31 miles) north of Mexico City - was once at the heart of the pre-Columbian Mesoamerican city of Teotihuacan.

Karenina Velandia reports.