I’ve seen that before. It is beautiful! All the caves and tunnels around here are a LOT smaller. Spider Cave in Schoharie County is completely dry and only about 3 feet (1m) high, but travels at least 3 miles/4.8km. There is another large cave that at one time was going to be commercialized. It was strung with lights (1930s-era sockets) and there are elevated wood plank walkways in some areas. But there was just too much water (springtime a waterfall) dripping down onto the walkway, so that endeavor was given up on. It’s inhabitants are bats, a few spiders, bats, some beetles, more bats and bats. Up in the John Boyd Thatcher State Park there is a cave that has as its opening a very wide slit that you can walk into (with your head slightly bent forward), but the farther you go the lower it gets. This cave has a stream in it that gets its water supply from two lakes (Thompson’s and Warner Lakes) which are many miles away. Spelunkers used to take inflatable kayaks/canoes in there. But alas, a few teenagers and young adults had slipped off the edge of the trail in front of the cave and were either severely injured or killed. The NY State Park Police blocked entry to the trail and the cave. Other caves around my immediate vicinity are very small - some just crawl spaces. Oh! There is one in Clarksville, NY just northwest of me that has as its entrance a large sinkhole (think big enough to place a truck/lorry in it. At the bottom of this is a hole just big enough to slide down into. Once inside, there is a room (to stand) with a two tunnels. The one to the south is a horizontal slit at the floor where you have to get on your belly and slide through for about 15-20 feet/4,5-6m. Then it simply dead ends! Now the other tunnels is nice! It leads to a third tunnel with a fast-flowing stream that runs through it. This stream originates from the Alcove Reservoir, passes beneath Lawson Lake and then through Clarksville. I’ve followed it upstream for a way, but turned around as a group of college kids were heading down in their inflatables. Not too much room to pass by each other. The beavers like to build a dam at the end of Lawson Lake. One time - after much rain - the dam gave way and a flood headed toward Clarksville. There were several kids in the cave at the time. The cave started flooding and all but one got out. There was a large rescue operation set in motion. The dive team from my fire company and from the next town north of us responded, as well as divers from the Sheriffs Dept. and the NY State Police. After an almost all night effort, they located the young man who had made his way to the highest point in this tunnel - and this was only providing enough space for his head to remain dry. Of course that cave was closed as well!
Of course, now that I am old and decrepit, I don’t venture into these wonderful areas any longer.