What's more terrifying than a late 17th-century prison in the middle of the Arizona desert that used to house some of the Southwest's most notorious inmates? If it's haunted, of course. Yuma Territorial Prison is absolutely crawling with the ghosts of those formerly incarcerated within its harsh, unforgiving walls, and you can experience the paranormal activity firsthand.

The infamous Yuma Territorial Prison began housing inmates as early as 1876 before it closed 33 years later due to overcrowding.

Since 1961, the facility has been open to the public as a historic park. Pictured here is the entryway through which prisoners left behind the free world — care to follow in their footsteps?

In total, just over 3,000 inmates were housed behind these thick iron bars. Their crimes ranged from murder to polygamy and everything in-between, with grand larceny being the most common offense.

As you walk up and down the corridors of the cellblock, notice how much the conditions differ from modern jails. Thick adobe walls kept temperatures bearable, but near-constant exposure to the desert elements has to do a number on one's soul, nevertheless.

Six inmates were crowded into each cell, their bunks forged from pure iron. Would you be comfortable sleeping here every night?

It is unclear exactly how the prisoners were grouped together, but we do know that the facility was co-ed. The youngest inmate was 14; the oldest 88.

Prisoners who required severe disciplinary action spent a night or two in the Dark Cell. Just gazing into this soul-sucking abyss, devoid of all life, gives us the heebie-jeebies — so imagine living in it.

Visitors brave enough to enter the Dark Cell should prepare to encounter energy so heavy, it can almost be described as suffocating. After all, only the most notorious inmates were banished to this lonely and forgotten place.

Last year, USA Today

ranked Yuma Territorial Prison the "Best Haunted Destination" in the U.S. It's easy to understand why — given the rich and storied past that still very much lives on within these walls.

Between death row inmates, a suicide, fatal riot, and botched escape attempts, the prison experienced its fair share of violence Paranormal activity is commonplace, with reports of everything from ghostly footsteps to disembodied voices shouting "get out!"

During your visit, climb up the renovated guard tower to enjoy 360-degree views of Yuma. A nearby observation deck showcases the Colorado River, old Fort Yuma, and 1915 Ocean-to-Ocean Highway bridge, among other iconic sights.

You can also explore the 3,600 square-foot prison museum, which features original artifacts and a video presentation. A gift shop offers memorabilia such as T-shirts, caps, keychains, books, and even handcuffs!

Don't forget to check out the cemetery down the hill from the prison.

We don't know exactly who lies in rest here or how they died, but one thing is certain: there's no shortage of angry spirits walking these grounds.

The park is open daily from 8 a.m. until 5 p.m. From June 1 thru September 30, hours are modified to 8 a.m. until 4 p.m. Thursday-Monday (closed Tuesday and Wednesday.) Admission is $8 for everyone 14 and up, $4 for ages 7-13, and no charge for children six and under. Visit the website or Facebook page to learn more.

Have you ever been to Yuma Territorial Prison? If so, did you experience any paranormal activity? Let us know, and check out our previous article for more haunted places in Arizona where things go bump in the night.