In April, much of the world ground to a halt.

No one not an expert in such matters could have foreseen it, maybe not even Paul the psychic octopus. Nothing more remote from our overflowing cup of concerns and anxieties could have been imagined — a volcano with an unpronounceable name (Eyjafjallajokull) in Iceland. But the vast ash cloud it spewed over northern Europe caused the most chaotic flight disruptions since Sept. 11, 2001.

Among the millions of stranded travelers was U.S. President Barack Obama, unable to attend the funeral of Polish President Lech Kaczynski. Kaczynski, together with dozens of his country's political, military and religious leaders, had perished days earlier in an episode so bizarre it seems in retrospect a worthy herald of the volcano. Their plane crashed in thick fog en route to the Katyn Forest in western Russia, where in 1940 Polish military officers were massacred by Joseph Stalin's secret police.