By Laura Koran, CNN

(CNN) – How many people would lay down their lives for a stranger?

It’s the question at the center of the new documentary “Besa: The Promise,” which premiered last weekend at the San Francisco Jewish Film Festival.

The filmmakers’ answer: “Albanians would.”

During one of humanity’s darkest chapters, when millions of Jews, gays, communists and racial minorities were rounded up across Europe, many Albanians put up a fight to save complete strangers.

They risked their lives to shelter displaced Jewish families under Italian, and later German, occupation during the Holocaust. Many in the small, predominantly Muslim country in southeastern Europe took refugees into their homes despite the risks and the cost, passing their guests off as family members to keep them safe.

CNN’s Belief Blog: The faith angles behind the biggest stories

At the core of this effort was a concept called “besa,” an Albanian code of honor that holds a person’s oath as sacred.

Under besa, a guest in one’s home must be protected at all cost. The code is uniquely Albanian and is cited in the new film as the main reason that Albanians opened their borders and their homes to displaced Jews when many others in Europe turned them away.

The code is fueled in part by the tenets of Islam under which saving a life is a blessed act.

Until recently, this chapter of history remained relatively unknown, hidden by the decades of isolation that Albania fell under following World War II.  Read further in CNN