(CNN) — North Korea has drawn a small but steady flow of US travelers since easing restrictions on American tourism in 2010

But after September 1, 2017, US citizens are barred from visiting the Hermit Kingdom -- so called for its isolationist policies.

According to the US State Department , the ban has been instituted because of the "serious and mounting risk of arrest and long-term detention of US citizens ..." and "imminent danger" posed by North Korea's "arbitrary system of law enforcement."

The policy follows the death of 22-year-old Otto Warmbier, a University of Virginia student who was detained in North Korea for attempting to steal a propaganda banner. Of the 18 people detained since 1995, 16 have been Americans, including three US citizens still in North Korean custody.

Some tour operators have already stopped taking Americans, including Hong Kong-based Eastern Vision and China-based Young Pioneer Tours -- the company that arranged Warmbier's visit.

"Our decision (to stop taking American travelers on tours after Otto) was based on the escalated potential consequences for Americans who may be detained," Troy Collings, managing director of Young Pioneer Tours's North Korea operations, tells CNN.

"I don't think Americans are in danger of arbitrary arrest, but the (detainment) statistics speak for themselves."

A last-minute influx

Despite government warnings, many Americans have been compelled to see the country for themselves before the ban took effect.

One such traveler is Jeff Barnicki, who squeezed in a last-minute trip with Beijing-based Koryo Tours last week.

"As an American, I may never be able to go back, so just getting there once was better than not going at all," Barnicki tells CNN. "North Korea is a mysterious country. The more I learned, the more I realized how little I knew about the place -- and the more curious I became."

The US will ban American citizens from visiting North Korea starting September 1. CNN's Will Ripley talks to some of the last American tourists to visit before the ban begins.

He says the experience helped him understand why North Koreans vilify the US -- at least, in political rhetoric.

"North Koreans grow up being constantly reminded that the US killed 33% of their population and leveled their entire country (during the Korean War from 1950 to 1953)," he says. "They believe that if they didn't have missiles and nuclear bombs, the US would have invaded by now."

While anti-American sentiments pervade political propaganda, Barnicki didn't feel threatened or unsafe.

Instead, he found that the people he interacted with were generally warm and welcoming.

"One guide was actually embarrassed when he saw me flipping through some anti-American propaganda postcards," Barnicki recalls. "He laughed and told me: 'Please try and understand our politics.'"

Inside the Hermit Kingdom

The vast majority of travelers to North Korea are Chinese, accounting for more than 100,000 tourist arrivals per year. But among non-Chinese travelers, Americans are actually one of the larger groups.

According to Koryo Tours, which has been facilitating North Korea visits since 1993, roughly 20% of non-Chinese tourists are American.

The largest Western groups are from Britain, the rest of Europe and America, Simon Cockerell, general manager of Koryo Tours tells CNN.

"I'd estimate 1,000 travelers a year come from the US."

For some, visiting North Korea poses an ethical conflict because of the country's history of human rights violations. The US State Department also questions tourism revenue, and how it's spent.

"It is entirely possible that money spent by tourists in the DPRK goes to fund (weapons programs)," the government memo states. "We would urge all travelers, before traveling to the DPRK, to consider what they might be supporting."

But for travelers such as Barnicki, the opportunity to interact with an isolated community outweighed these concerns.

"I honestly did not spend much money there -- seriously, maybe $300 on souvenirs and beer -- and it appeared that the money went to a local economy, which really needs it, not nukes and missiles," he says.

"(After the ban), there will no longer be the brief human interaction that the North Koreans get with the American tourists. They will now only hear how bad we are from their media, and Americans will only hear how bad (North Koreans) are from our media. It is a losing proposition for both sides."

A tour de force

For anyone except Americans and South Koreans -- who are already prohibited from entering -- it's relatively easy to obtain a North Korean tourist visa, but all travelers must book a guided tour.

Ranging from three to 21 days, guided journeys with Koryo Tours can cost anywhere from $1,336-$5,476 per person -- more for personally designed private itineraries, though totally independent travel is not an option.

The packages cover round-trip flights between Beijing and Pyongyang, visa fees, food, transport and accommodation.

Most itineraries start in the capital of Pyongyang. It's the most developed city in North Korea, with an international airport, metro, museums, monuments, parks, bars and festivals.

Another well-trodden tourist destination is the Demilitarized Zone (DMZ), a 2.5-mile-wide (4-kilometer) treaty zone that essentially splits North and South Korea across the middle.

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After touring the DMZ, travelers might also explore nearby Kaesong old city -- home to a dozen UNESCO world heritage sites, many of which date to the 10th-century Koryo Dynasty.

Some travelers have been so fascinated by the experience that they've visited again and again. American Patrick Border, for example, has been to North Korea seven times.

"I was once stationed in South Korea and have always had a burning curiosity how the other half lives," says Border, a US Air Force veteran. "When the ill-fated decision to ban travel was announced I took the last lawful trip I could.

"The tour guides are friendly and, over the years, I have bonded with many of them. We are citizen diplomats ... [North Korean] people need to meet Americans to realize that the party line is false. Without that, the Workers' Party of Korea [the founding and ruling political party] can say whatever it wishes unchallenged."

Beyond the basics

For those with a flexible timeline and budget, a trip to North Korea could include anything from skiing to beach trips, biking, golfing, hiking, circuses, film festivals, and kayaking. There is even an annual marathon and a beer festival -- though the latter was canceled this year.

For more adventurous travelers, 9,002-foot-tall Mount Paektu, near the Chinese and Russian borders up north, provides a challenging excursion.

The mythological birthplace of the Korean race, the active volcano left an enormous crater in its wake following the massive "Millennium eruption" in 946 AD.

"It's an enormous volcano of the Mount St. Helens variety, without lava, but instead blown-out dry rock and rubble, from huge boulders down to sharp rocks and pebbles," recalls Border, who visited in August.

"In the base of the crater, there's a blue freshwater lake, accessible by a steep tram or a lift. It is a shocking exhibit of volcanic activity which is not seen anywhere else in the peninsula."

To the west, along the China border, Sinuiju provides more low-key outdoor activities, thanks to scenic rural roads, hot springs, hiking and waterfalls.

The country is also home to long stretches of nearly untouched coastline and clear water, best experienced at the sandy beaches near Wonsan in the southeast.

About 30 minutes west of the coast by car, Masikryong Ski Resort crowns Taehwa Mountain -- complete with 120 hotel rooms, roughly a half-dozen ski runs, plus a peppering of bars and restaurants.

"There's much more to North Korea than most people realize," says Border. "If this travel ban is lifted, I may go back to see the film festival, or watch the marathon runners. If I were younger, I would run the race myself."

A new conversation

For many travelers, spontaneous interactions with North Korean citizens -- often at local bars or major festivals -- are the most rewarding aspect of a journey.

American Jake Pezzulo says that his conversations with North Koreans upended commonly held notions.

"A lot of Americans think of North Koreans as either robotic and humorless -- or imagine they are constantly looking over their shoulders out of fear of running afoul of their government," Pezzulo tells CNN.

Swimmers gather in a Pyongyang leisure complex wave pool. ED JONES/AFP/AFP/Getty Images

"Even as an (American), interacting with the staff in some of the locations we visited, people would crack smiles and joke around. One person even showed me family photos on her cell phone."

While some stereotypes ring true -- North Koreans do indeed cut grass with scissors and many people parrot political propaganda -- it's not hard to find common ground.

"They're not actors put on for tourists, they're not all KGB agents pretending to be locals," says Cockerell. "The North Korean public is not the Taliban. They often have quite similar hopes and dreams as you or I do.

"They're a little more approachable during celebrations or after work with a little social lubrication, in the bottled form -- that can help people to get up the courage and will to interact with funny-looking visitors."

Follow the rules

Whether propelled by earnest curiosity or simply bragging rights, every visitor must heed North Korea's strict laws and stay mindful of cultural expectations.

The rules range from non-severe social missteps -- such as taking images of local people without permission -- to potentially serious infractions, such as tampering with propaganda, practicing religious missionary behavior or disrespecting past and present leaders.

It's suggested to bow when visiting monuments and statues, such as the Mansudae Monument in Pyongyang, where 72-foot-tall bronze statues of former North Korean leaders Kim Il Sung and Kim Jong Il tower above. For North Koreans, it's compulsory, but bowing is optional for foreigners.

Photography is another common concern. Travelers can take pictures and videos -- but not of military operations, construction or other unapproved sites. It's advised to ask a guide before snapping away.

"There is this common misconception that if you take a picture with a soldier in it, you'll be detained, but this isn't realistic at all," says Cockerell. "Most of the time it just causes hassle, irritations and headaches."

Tourists must stick by their guide at all times, unless they're told it's OK to wander off -- for example, within the hotel at night, or in select department stores.

"The most important thing for travelers to understand is that North Korea has very strict rules and very strict laws. Whether you agree with it or not, you mustn't break the law," says Cockerell.