Stone formations lure thousands of visitors each year to Mammoth Cave. Volunteers who help map the world's longest cave have explored 10 more miles, pushing it past the 400-mile mark.
Stone formations lure thousands of visitors each year to Mammoth Cave. Volunteers who help map the world's longest cave have explored 10 more miles, pushing it past the 400-mile mark. AP
Stone formations lure thousands of visitors each year to Mammoth Cave. Volunteers who help map the world's longest cave have explored 10 more miles, pushing it past the 400-mile mark. AP

Mammoth Cave hits 400 miles

February 21, 2013 6:20 AM