CNN leaves the metric description of the tunnel in with feet following in parentheses. http://www.clickondetroit.com/news/28855144/detail.html
The unfinished tunnel is 298 meters (977 feet) long, two meters (6.5 feet) high and about half that wide, and is thought to be intended for smuggling drugs, the National Defense Secretariat said. The tunnel, which has lighting and ventilation, is thought to have started a year ago and reaches 100 meters (328 feet) under the U.S. border.
