Mexico City

Thor visited North America's most populous city frequently as a child, hanging out in a restaurant called Hacienda de Los Morales on his way to vacation with his family in the coastal town of Zihuatanejo. When he returned to the city to research a book orbiting the city's drug cartels, the restaurant was still there, but a lot had changed.

Eager to get a firsthand look at the violence, Thor joined a convoy headed toward a safe house where members of a cartel were allegedly holding hostages. He says that the neighborhood run by the cartel reminded him of Afghanistan. "They had kids on the roofs watching us and a motorcycle tailing the cars," Thor remembers. "The cartels operate a lot like the Taliban."