Ratlines: a series of rope steps by which men aloft reach the yards.
— The Oxford Companion to Ships and the Sea
In the old navy, ratlines (pronounced "rattlin's") referred to rope ladders attached to the masts. When a sailing ship began to sink, those ladders would offer the only safety to sailors who'd missed the lifeboats, so ratlines came to mean a "means of escape.”
In today's military, ratlines refer to an enemy's means of escape—particularly clandestine escape. Ratlines in this sense were used by combatants during the Iraq War, the Yemeni Civil War, the Somali Civil War and the War in Afghanistan.
But by far the most infamous ratlines were those used by members of the SS at the close of World War II.
The SS called their ratlines Klosterrouten ("cloister routes"), because sympathetic Catholic clergy ran them. They allowed SS to escape the Fatherland through Italy, Spain and Switzerland, then sail under fake names to safe havens in Argentina, Brazil, Chile, Paraguay and Uruguay.
The Nazi ratlines were organized as early as 1943 by a Croatian priest and an Austrian bishop, with the blessing of Hitler's private secretary, Martin Bormann, and the acquiescent blessing of Pope Pius XII. Without voicing despair, these men foresaw Germany's fall and hoped to set up Nazi governments in exile.
The ratlines helped as many as 300 SS escape, including Josef Mengele ("the angel of death"), Klaus Barbie ("the butcher of Lyon") and Adolf Eichmann ("the architect of the Holocaust"). Ironically, forged papers allowed many SS to pass themselves off as Holocaust survivors.
Hans-Ulrich Rudel (who became a top advisor to Argentine President Juan Perón) openly praised the Catholic church for operating the ratlines in a speech in 1970.
"One may view Catholicism as one wishes," he said, "but what the church, especially certain towering personalities within the church, undertook in the years after the war to save the best of our nation must never be forgotten.
"With its immense resources, the church helped many of us go overseas in quiet and secrecy, thus counteracting the demented victors' mad craving for revenge and retribution."
POSTSCRIPT: Speaking of retribution, the world's only Nazi-hunter, Brooklyn-born Efraim Zuroff, is still on the trail today, even though living Nazis are few. In four decades of detective work, he has tracked down over 3,000 of them in 20 countries. "The passage of time does not diminish the guilt of the killers," he told The Guardian this month.