Bear cave
From Futurepedia, the Back to the Future Wiki
The bear cave was a cave near the McFly Farm in 1885 and the Pohatchee Drive-In in 1955. Marty McFly had to drive a little to reach it, but not before escaping the Pohatchee followed by the U.S. Cavalry. After both parties had passed, he noticed the smell of gasoline, spewing out of the fuel line that he ripped.
Marty also discovered that a black bear lived in the cave where he parked, forcing him to run out quickly and ditch his boots. He crested a hill and slid down hitting a fence rail, knocking himself cold. Seamus McFly recovered him and took him to the house.
