Jay Austin and Lauren Geoghegan, both 29, last year quit their office jobs in Washington, DC, to embark on the journey. Austin, a vegan who worked for the US Department of Housing and Urban Development, and Geoghegan, a vegetarian who worked in the Georgetown University admissions office, decided that they're were wasting their lives working.

"I’ve grown tired of spending the best hours of my day in front of a glowing rectangle, of coloring the best years of my life in swaths of grey and beige,” Austin wrote on his blog before he quit. “I’ve missed too many sunsets while my back was turned. Too many thunderstorms went unwatched, too many gentle breezes unnoticed.”

The couple documented their year-long journey on ​Instagram and on a ​joint blog. As The New York Times ​put it, they shared "the openheartedness they wanted to embody and the acts of kindness reciprocated by strangers."

“You read the papers and you’re led to believe that the world is a big, scary place," Austin wrote.

“People, the narrative goes, are not to be trusted. People are bad. People are evil."

“I don’t buy it," he continued. "Evil is a make-believe concept we’ve invented to deal with the complexities of fellow humans holding values and beliefs and perspectives different than our own... By and large, humans are kind. Self-interested sometimes, myopic sometimes, but kind. Generous and wonderful and kind.”

However, Austin and Geoghegan's dream trip came to a tragic and gruesome end when they got to Tajikistan, a ​weak state with a known terrorist threat that shares a border with Afghanistan, where ISIS and other terrorist groups are ​highly active. They were riding their bikes through the country on July 29 when a car rammed them, ​​according to CBS News. Five men got out of the car and stabbed the couple to death along with two other cyclists, one from Switzerland and the other from the Netherlands.

Two days later, ISIS released a video showing the same men sitting in front of the group's black flag. They looked at the camera and vowed to kill "disbelievers," ​according to The New York Times.

Some conservatives have framed the tragedy as a cautionary tale about not just the perils of travel but also naivete in general. In their telling, an overly generous understanding of human nature is behind much of today's progressive movement, including calls to radically scale back immigration enforcement and policing and support for socialism.

Some liberals, for their part, view Austin and Geoghegan as simply unfortunate. Experts on the region ​​told The Washington Post: "Central Asia generally is fairly safe."

CORRECTION: A previous version of this article said Tajikistan has a "known terrorist presence" and that the couple biked through "ISIS territory." It is more accurate to say that Tajikistan faces a threat of terrorism and is near to northern Afghanistan, which has a large terrorist presence.