Here in 2015 just about every place on earth has been explored and mapped, except for the deepest oceans there are very few spots unseen by human eyes.
But one of those rare places was recently explored for the first time right here in Arizona. It's a limestone cave at the edge of one of the natural wonders of the world.
At the back of a cave which has been a popular tourist spot for nearly 100 years, a group of cavers started digging, and they discovered new caves never before seen by human eyes.
Only about 15 people on earth have seen inside the cave.
The Grand Canyon Caverns are right off Route 66, about 3 1/2 hours northwest of the valley.
The main caverns were explored in the 1920's, and they are developed today with comforts like a walkway, lights, and oddities like a mummified bobcat from the 1800's. There is also a stockpile of food placed in the cave by the government after the Cuban Missile Crisis, to feed survivors of a nuclear attack.
Anybody can see those things, but now FOX 10 is taking you off the paths, deeper into the cave, and deeper underground.
Michael Dashofy and a group of Arizona cavers knew there was more to the Grand Canyon Caverns than already explored, because of a breeze they could feel blowing through the existing caverns.
"We decided to start digging because the air was coming through the crack," said Michael Dashofy.
So they knew there was another big cave down there?
"Yes, and we haven't found it yet, but we found a lot," said Dashofy.
The caverns are a dry cave complex, not wet. So you don't see the big stalactites or stalagmites, but as we descended into the new secret entrance, there are formations like popcorn. They look like flowers growing out of the cave wall.
But there is more descending to do. So weird, literally climbing down inside the earth with stacks of rocks everywhere, the hope is that they don't come down.
Finally, about 205 feet down the group came to a newly discovered area.
"Nobody saw this for millions of years," said Dashofy.
"When we found this entrance everybody was so excited because we finally had broken through," he said.
Before this story, only 15 people had ever seen what is inside. Simply put it is beautiful, crystal formations that took tens and maybe hundreds of thousands of year to form a line on the ceiling. Other crystals litter the floor; it's a result of ten years of hard digging to remove rocks and open up this Arizona treasure. The work was done by a small, but dedicated group of cave explorers.
"Nothing has been touched, everything is untouched, that's the goal, to go into a virgin cave, to go where no man has gone before," said Dashofy.
That goal was completed, but it's time for the most important part of caving, getting out safely. After a few more tight crawls, the group returns to the massive entrance to the main caverns.
It's an adventure deep in the earth, and at the same time out of this world.