Two days ago I entered Great Smoky Mountains National Park. This is a large park that includes parts of both Tennessee and North Carolina. It is also the most popular national park in the US, with more than 11 million visitors last year.
About 70 miles of the AT are in the Park, including the highest point on the AT, which is at Clingman's Dome (6,643 feet).
The Park is an ecological hotspot, with more tree species than Europe, a large number of salamander species, and the highest density of bears in the Eastern US. In fact, research that I was reading about said that there are a staggering two bears per square mile of Park.
I saw a square mile's worth of bears the day I entered the Park. I had stopped for a lunch break and had just opened a package of teriyaki flavoured beef jerky (not something I eat at home, but man it's delicious). I heard a crash in the woods just ahead and immediately two bear cubs appeared on the trail only 20 metres from me. One ran into the bush on my left and the other climbed a tree right in the edge of the trail. They were cute, but my mind immediately raised the question "Where's Momma?" I through my lunch back in my backpack, stuck my whistle in my mouth (my thin defensive line against bears) and carefully walked up the trail. By this time the cub in the tree had slithered down, making a juvenile growling noise, and run back into the bush. I never saw or heard Momma.
That night we had a yo-yo hiker stop at the shelter. A "yo-yo" thru hiker is someone who completes the entire AT and then turns around and does it again in reverse. It was about 8:30 pm, an hour after dark, when the hiker emerged from the night looking for water. He went to the spring, gobbled something cold and crunchy from his bag, and then headed back into the night. He said he wanted to make it to a shelter 14 miles away, for a total walk of 41 miles that day. For some the AT is a 2,189 mile ultra marathon, and I guess this guy was in the vanguard.