I've been reading through Essential Solitude, which is a two-volume collection of letters between H.P. Lovecraft and August Derleth. Actually it's mostly Lovecraft's letters, as not that many of Derleth's survive, but then again, most people are probably more interested in HPL anyway. Still, it's nice to see both sides of the conversation when I can.
Last night I came across a long letter from HPL, describing a visit he had made to Tennessee in the early 1930s. During that trip, Lovecraft visited Lookout Mountain and Ruby Falls. It's been years since I've been to either, but I always find it kind of interesting when my path crosses that of any of my writer idols, and Ruby Falls is not only a place that both HPL and CRR have visited, but it's a particularly Lovecraftian place anyway.
If you're not familiar with Ruby Falls, it's an underground waterfall inside of Lookout Mountain. It was discovered by accident in 1928 while a man named Lambert was digging a shaft to another cavern, planning a tourist attraction. He certainly got a better attraction than he expected. The falls would only have been known for a few years when Lovecraft visited, and of course he latched on to a particularly macabre fact about the falls. Since there had been no natural opening to the cavern, no human had ever seen this spectacular sight until its accidental discovery. For untold ages the falls had thundered in the pitch darkness with no eyes to see it.