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For Western radicals bent on joining the Islamic State, leaving their families to go to the front lines in Syria or Iraq takes less than a few days and $1,000, and the terror group even has a blogging tour guide -- a female Scottish jihadist -- to smooth the journey.

“Prepare your pristine feet to get covered with dust,” urges 20-year-old Aqsa Mahmood, who left her family in Glasgow last November to travel to Syria to "become a martyr." From Raqqa, she has published a series of advice pieces on Tumblr for Westerners who want to follow in her footsteps.

The beaten path goes through Istanbul, an international hub in a country that straddles – both geographically and culturally – the West and the Middle East. Thousands of men and some women have dropped out of Western society to join the bloodbath, their way well-marked by predecessors.

“A large majority of foreigners joining the Islamic State are arriving in Iraq and Syria via Turkey,” said Ryan Mauro, national security analyst and adjunct professor of homeland security at the nonprofit Clarion Project, a New York-based research institute that focuses on the threat of Islamic extremism. “A flight to Turkey doesn't usually arouse suspicion because there is so much travel between Europe and Turkey.”

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Last month, Turkish President Recep Tayyip Erdogan, in New York for the UN General Assembly and speaking to the Council on Foreign Relations, estimated that 6,000 foreign fighters have entered Turkey, even though "they have been banned" and are “under control." Implicit was that Turkey was just the last stop before their final destination – the land claimed by Islamic State.

It’s a journey a frightening number of radicalized Westerners have made after becoming sucked into the violent vortex of images and rhetoric posted online by Islamic fanatics. One-on-one contact via email forums and social media draws recruits closer, and prepares them to make the ultimate commitment.

For those with a Western passport, getting to either of Istanbul’s two major airports, Ataturk and Sabiha Gokcen, is easy. One-way fares may arouse suspicion, but round-trip tickets to Istanbul from the most common origins of Western jihadists range from as little as $300, from Munich or Paris, to just under $1,000 from Los Angeles.

In addition to being a NATO member and Western ally, Turkey is a popular tourist destination, with 15.5 million visitors in the first six months of 2014 alone. Ataturk airport was Europe’s fifth-busiest airport in 2013, and in addition to it and Sabiha Gokcen, Antalya airport on the Mediterranean coast takes in more than 25 million passengers per year with flights to and from most European capitals.

With so many visitors flocking to Turkey for legitimate reasons, jihadists can easily blend in.

Those entering the country may apply online for a visa or obtain one at the airport. The document provides its holder 90 days to roam Turkey within a 180-day period.

In her role as an online travel guide for jihadists, Mahmood claims airport security in Turkey is relatively lax -- if the authorities assume they are dealing with a tourist.

“You are unlikely to get stopped at customs, as long as God is willing and you haven’t got an international criminal record,” Mahmoud wrote in a recent post.

She dispenses tips, including avoiding packing knives, hiking boots or camouflage clothing. Dissuade security officials from opening bags by wrapping them in plastic and affixing “fragile” stickers, Mahmoud advises, and memorize a few tourist attractions to rattle off for inquisitive officials.

Once on the ground and out of the airport, jihadists connect by phone with handlers using arrangements made online before the trip. If the jihadist has followed Mahmoud’s advice, they will have brought an unlocked Android phone to Turkey and have bought a SIM card from Turkcell, the nation’s largest mobile phone company.

The intermediary, who Mahmoud referred to as an “acquaintance,” organizes the logistics for getting to and crossing the border into Syria with the help of Islamic State’s “Madrassat al-Hudud,” a quasi-official border bureau.

“Call the number, let them know that you’re in Turkey and that you want to make hijra to al-Dawlah,” Mahmoud wrote in another recent post, using an Arabic phrase for migrating to the border region.

In a cheeky style that both underscores her youth and Western upbringing and belies the gravity of the mission, Mahmoud advises recruits to keep the phone numbers hidden, using paper and false names.

“Not under a moniker such as ‘Usama bin Laden,’ though, okay?” she wrote. “Promise? Good.”

Getting to the caliphate through Turkey may not remain as simple as it has been. Since May, Turkey has been under international pressure to step up policing at Turkey’s smaller, southern border airports at Hatay and Gaziantep, efforts that could choke off jihadists connecting from nearby nations such as Saudi Arabia, or flying down from Istanbul.

"We check entry and exit points, but then you know, these people move, of course, from other parts of the border,” Erdogan told the Council on Foreign Relations. “We try to keep tabs on them. But our goal is to try and ensure that foreign fighters do not go through our borders. We're very determined to prevent them from doing so."

In recent days, with Islamic State fighters converging on the Kurdish Syrian city of Kobani, which sits on the Turkish border and has absorbed tens of thousands of Kurds routed from their villages, Turkey has sent troops to secure the border. Erdogan is under pressure from Western allies to help stop the Islamic State advance, but for now Turkish troops have not engaged the terrorist army.

According to Mauro, whatever steps Turkey claims to have taken to shut off the jihadist pipeline are simply for show. Erdogan’s administration has supported the multi-fronted effort to overthrow Syrian President Bashar Assad, the fight that spawned Islamic State.

“It has not stopped this flow of fighters,” Mauro said. “It is common to see ISIS members boasting on social media about their open presence in Turkey, including Istanbul.

“The Turkish government would like to play stupid like it can't detect and stop jihadist travel through its border, but the Erdogan government has no problem curtailing civil liberties in order to stifle dissent,” he added.

Whatever the situation at the southern airports, south-bound buses from Istanbul continue to roll, providing anonymity at a relative bargain. For the U.S. equivalent of $1.38 on the TL 3 metro, one can get from Istanbul’s main airport to Bayrampasa bus station. With no police or security checks, he or she can board one of the buses operated by more than half a dozen companies that travel back and forth to Gaziantep and Hatay on a daily basis. The cost is roughly $35 to $40 and the ride takes 15 to 20 hours.

The buses used to travel across the border into Syria, but no longer.

“We had to stop six or seven months ago, but we go to Hatay,” said an official with HAS, one of the transport companies.

An official at another bus company told FoxNews.com five buses carrying an average total of 320 people make the trip to Gaziantep every day. As a private company, it is under no obligation to record who gets on or off.

“Of course, if we suspect them we watch their bags, but what they do when they get to the city, that is their business,” the official said.

Sources told FoxNews.com some buses are subject to random stops and searches by the police, but the probes are typically not intensive.

Once at a bus station near the border, Mahmoud warns recruits not to take up offers from strangers to take them over the border. Instead, take a taxi to a pre-arranged safe house, she advises. About $50 is the going rate, and once there, food will be provided until notification to cross is given. The crossings happen at night and recruits are often made to leave their luggage behind.

A long hike guided by flashlight brings the new jihad recruit across the border and into the land Islamic State claims as its caliphate.

“Be sure to take a breath of fresh air,” Mahmoud writes. “Because that’s how Shariah feels.”