(WBIR-South Knoxville) It seems like something interesting is always going on at Ijams Nature Center in South Knoxville.

Tuesday afternoon children got a peek at something that is hardly ever open.

It was Habitat Endangered Species Day at Ijams and day campers spent part of it in a cave.

Stephen Lyn Bales explained the cave is locked with a heavy iron gate most of the time to protect the Berry Cave Salamanders that live there.

The campers carefully crawled in to explore.

"Well, this is a pretty safe place to cave. There's not a lot of stalactites, it's a much newer cave. But the interesting thing is that it gets smaller, and smaller and smaller so by the time you get to the end I am usually leading the way and I am the stopper. If I cannot crawl any farther than the kids can't get past me," he said.

He said the cave experience today is rare.

"This is only done once," he said. "In fact we haven't opened this cave up for this in four or five years. I haven't been in the cave in a long time. So I only do it for special classes and this is about endangered species."

Ijams offers activities all year. Check their website for information.