This important part of the world's history is the only one remaining fully intact and it lies in southwest South Dakota. At one point, this site occupied over 13,500 square miles and was placed to protect the entire United States during the extreme tensions between countries during the Cold War. Back when it was built, it was a top secret location. Today, it is open for visitors to see up close and learn about the lengths at which we would go to protect our homeland.

Stop by for a tour and you won't regret it; you will leave with important knowledge of the past.

Your first stop should be the visitors center to the Minuteman Missile Historical Site.

The visitors center will give you an introduction to what this historical site is all about, the Minuteman Missiles created and stored to deter potential nuclear attacks. Here, you can also get tour tickets that are required for one of the three areas included here and well worth grabbing. This state of the art center is full of information and artifacts, but the real historical journey begins at Delta-01.

The Delta-01 Launch Control Facility has been left exactly as it was decades ago, and you can enter it yourself.

Underground and behind this 8-ton steel blast door, humorously decorated by the military members who served here back in the 60s, is where 24/7 watch was kept in order to have missiles at the ready to be launched at any moment.

The control room is small, but full of historical significance. It is highly fortunate that it never came of use, and when stepping foot in here, you can sense the feeling of importance that this very room could have had but luckily did not.

This senior control panel has the real, untouched controls to launch the missile.

The tour here is a sobering experience that shows just how on edge the world was during this period. On the raised metal box on the right side, there is the actual key slot to launch the missile - such an easy motion for one person to make, with a result that is one of the most powerful forces ever created.

After visiting the Delta-01 Launch Facility, you can take a look at the very missile itself.

This glass-capped dome allows a view into the missile silo with an actual, now unarmed, missile.

The missile sits suspended in the silo the same way it did all those years ago up until just a couple of decades ago

This view is something else, and may be a little nerve-wracking for someone who is afraid of heights. It goes down far...

...really far! 80 feet down, in fact. Back in the '60s to the '90s, hundreds of these silos existed. Pretty much all of them have been filled in or otherwise destroyed and decommissioned, and this is one of the only ones left intact.

To learn more about this site and its history, location, and more, click here.

Take a look at photographs from South Dakota in the 1960s to really take a trip back in time.