Thousands of people from the United States, Europe, and other Western countries have run off to join ISIS. Exact numbers are difficult to discern, but of the more than 20,000 foreigners who have traveled to Syria and Iraq to join the so-called Islamic State, somewhere around 3,500 of them come from the West.

Their motivations vary from disenfranchisement with their own culture to being pissed off at their parents (no, really), and it is no secret that most of them are finding their way to Syria by crossing the border from Turkey. Meeting with several individuals in Kurdistan with inside knowledge of how this phenomena is taking place, SOFREP has identified a key choke point in the underground ratline that takes Westerners who want to join ISIS from their home countries to the Islamic State: Ataturk International Airport in Istanbul.

Named after the founder of the modern Turkish state, Kemal Ataturk, the airport is the largest in Turkey. After getting cyber-recruited by one of the many ISIS members conducting such activities on social media, the would-be jihadis hop on the airplane to Istanbul with instructions with what to do next.

The international terminal at Ataturk Airport is pretty much what you would expect from any major airport in America or Europe. Dozens of shops line the terminal selling fashionable handbags, duty-free liquor, and Starbucks coffee. One unique feature of the terminal is that it contains a mosque where Muslims who are traveling can go and pray while they wait for their connecting flights or prior to leaving the airport. I snapped a picture on a recent visit.