Reverse biased breakdown
A normal diode will will break if you go over the reverse breakdown voltage if the current is not limited.

A zener diode is made to work in that area. 
You can compare a reverse biased zener diode with a forward biasd diode but with a much higher forward voltage (like if you set a few of them in series).

There are also avalanche diodes http://en.wikipedia.org/wiki/Avalanche_diode
These are made to survive the reverse brakedown.

I hope this helps you