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.