If you close your eyes and picture a mental image of Iowa, this is likely not what comes to mind.  A massive underground cave system stretching for miles underneath the karst topography of northeast Iowa.

Scott Dankof, Grimes, Iowa: “Coldwater Cave is kind of a cave within a class by itself. You don't find things like this in Iowa especially underneath a corn field or a pasture.  You just don't expect to see it.  Size wise it is so huge and the main passage is so big and large it's like a subway tunnel. Most Iowa caves are small, wet, muddy and not really pleasant.”

Despite its size, the conditions and means of descending into Coldwater Cave are not for the casual tourist. The crew of Iowa Outdoors met up with members of the Iowa Grotto, a seasoned group of cavers intent on safely sharing the subterranean wonders of our state.

Tucked inside a modest shed and bunkhouse rests the main human-built entrance to Coldwater, a metal tube and ladder descending 100 feet into the darkness below.

Scott Siepker: “I’m a little nervous, I really don’t know what to expect.”

After lowering our television gear to a platform at the base of the ladder, it’s time for my first journey under Iowa’s surface.

Scott Siepker: “You know when I got down here I turned on my little headlight and I had this great little moment where I realized what’s in front of me and it’s pretty incredible.”

The absolute awe of an alien environment is nearly as eye-opening as the water temperature. Hence its name -- Coldwater Cave resembles an Iowa stream with water levels that fluctuate due to rainfall or snowmelt that eventually dumps into nearby Coldwater Creek.

Our journey, planned for the frigid winter days of February, came amidst an untimely thaw…raising the water level to our waistlines and pumping icy snowmelt beneath the topsoil and through the cave.

Doug Schmuecker, Cave Rescue Logistics: “We have a spotless safety record.  We've had just very few minor injuries over the years.  We watch the weather.  Just like today we're not taking you very deep.  Chances spring run off water levels coming up.  Water temperature, air temperature, you've noticed even some of you are starting to feel effects - early effects of hypothermia.  Basic caving requires a hard had and at least three light sources.  Here we go to wetsuits.”

Those wetsuits help by creating a thin barrier of body-heat and warmer water next to the skin…but our guides peg the day’s water temperature near 37 degrees with the air temperature at a balmy 47.  We head upstream to higher ground and I realize that safely traveling a small section of cave takes time and patience.

Doug Schmukar: “This is a beautiful area but you also got to realize you can get a long ways into this cave, have a problem, and it can get very serious.  I think you've all noticed just getting back out of here if you had somebody injured would be a major undertaking.  So we - we've always stressed safety up here and we will continue to.”

If you can safely navigate Coldwater’s slippery rocks and icy water flow you’ll discover some spectacular scenery.  A mix of formations dot the landscape – many of which were developed by mineral-laiden water over thousands of years.  Some descend as stalactites from the ceiling or stalagmites from the cave floor while newer formations like these soda straws are just beginning to take shape.

John Lovaas: “The earliest sediment that has been dated in the cave are around a quarter million years old.  So, that's all we can say is that there are sediments approximately that old in the cave.  Scientists would consider this a fairly young cave just based on a variety of technical indicators.”

Scott Siepker: “These are crynoids, also known as sea lilies.  They’re 450 million years year old.”

John Lovaas, Science Support Coordinator: “There are some pretty spectacular crinoids beds here in the cave.  Basically it's a case where a slab from the ceiling peeled off the ceiling and ended up on the floor and now we're able to walk on top of that slab.  Crinoids we know today as sea lilies in the oceans of the world.”

From fossils to flowstone, Coldwater Cave can present a variety of photographic opportunities.

Scott Dankof: “I started coming into the cave in 86 and pretty much immediately started taking photos.”

Scott Dankof has photographed Iowa’s tunnels and caves for nearly 20 years but some of his best work originates from the “crown jewel” of Iowa’s underground environment: Coldwater.

Scott Siepker: “What are the challenges of doing photography obviously in a cave?  Lighting?"

Scott Dankof, Cave Photographer: “Lighting is the biggest issue in this cave.  The walls depending on where you are at in the cave, dark colors eat your light, the water eats your light.  You have to use larger flashes, carry more gear, everything has to be in waterproof boxes.  Large passages like we're in now not a big deal.  Carry a tripod in a pelican box is what we use most the time.  You get into small passages, hands and knees, in the water crawling is a whole different thing.”

To date, explorers have discovered more than 17 miles of winding passages at Coldwater Cave. It’s a journey that began more than 40 years ago.

Discovered in the 1960’s by a trio of divers near Coldwater Creek, the cave captured the attention of Iowans and state government.  Local farmers Ken and Wanda Flatland had suffered numerous sinkholes on their land and heard stories of other farmers that had lost livestock down mysterious holes.  Experts later discovered Coldwater Cave ran directly underneath a section of the Flatland farm. With financial backing from the state legislature, the Iowa Geological Survey drilled a 94-foot hole for visitors to descend into the largest known cave system in the Upper Midwest.  But state officials quickly discovered it was not a casual tourist destination and scrapped plans for lighted concrete walkways. The raw nature of Coldwater Cave has kept spelunkers coming back time and time again.

Divers say the network of passages will still be here long after they’re gone but concede the cave faces challenges from human contact and runoff from farm fertilizers.

John Lovaas: “We're an ag country, where not too far from a college town, but you are truly in a wilderness, you know, where once you enter the cave and travel for sometime you can be two or three miles from the nearest exit which, you know, from the definition of wilderness it certainly is.

Scott: “The ultimate Iowa Outdoors.”

John Lovaas: “In a way it is.  A bit underground but yes.”