But why would 15th-century builders erect such an elaborate city on a narrow mountain ridge and fault line 8,000 feet above .
The earthquake that just shook the East Coast was caused by one of dozens of ancient fault lines that have lain dormant ...
The Ring of Fire is home to 75% of the world's volcanoes and 90% of its ... along the boundaries where the plates meet, called fault lines. The Ring of Fire is home to the deepest ocean trench ...