A look at migration trends behind the latest shipwreck off Greece

Wednesday's deadly shipwreck off southern Greece, involving a large boat carrying migrants that capsized after apparently rebuffing offers of help, is just the latest case of smugglers packing vessels full of desperate people willing to risk their lives to reach continental Europe.

The trip from Libya or Tunisia through the Central Mediterranean and north to Europe is the deadliest migratory route in the world, according to the UN's International Organization of Migration.

Here's a look at situation in the Mediterranean and some of the particulars of the latest tragedy:

What happened?

Greek coast guard, navy and merchant vessels and aircraft launched a vast search and rescue operation after the overcrowded fishing boat capsized and sank early Wednesday some 75 kilometers southwest of the southern Peloponnese peninsula.

So far, 79...