A wall of debris stretching about 30 miles (50 km) may be the remnants of a natural disaster that struck Mexico's Caribbean coast more than 1,000 years ago in an area where tourists now flock to beach resorts and ancient Maya ruins.
A huge tsunami is the likely culprit, propelling debris including boulders made of reef material ripped from the seafloor far inland, scientists said on Thursday.
The tsunami appears to have struck during the height of the ancient Maya civilization, but may not have caused a large body count because the area was not densely populated, they said.