SAN ANTONIO, TX (CBS/KENS) - A massive cave has been discovered under a San Antonio subdivision. While caving experts want to map it, local kids just want to explore it.

In the midst of some home construction a remarkable find: what could be the fifth largest cave in Bexar County.

They are boys doing what boys do, exploring around the neighborhood. And this group of 9,10, and 11-year-olds found a hole. So they did what boys do: they poked at it. One of the boys say, "I just stuck my hand in. It was kind of humid, so I took a picture." Another says, "We stuck our phones in it and found stuff inside it. It was really cool."

The pictures they took with the cell phone started a spelunking adventure and expeditions launched by their fathers, who want to remain anonymous.

The cave appears extensive with stalagmites and stalactites, features that rival some more famous caves in the area.

Caves do get some protection: in the Edwards Aquifer Zone, they can't be plugged without review from the Texas Commission on Environmental Quality.

The developer has placed grates over some of the smaller entrances and reportedly sealed up the larger crawl space.

But these boys may have opened up a can of worms, make that a can of cave spiders or beetles, to an underground world.