White tigers themselves aren't that rare. What's rare about King is that he doesn't have any defects, unlike many white tigers in captivity. All captive white tigers descend from one male white Bengal, hence the genetic defects suffered by many.
King-Bengal Tiger, Panthera tigris tigris
June 8, 2009
Busch Gardens Africa
Tampa Bay, Florida
Edits: border, adjust curves, adjust saturation
Taken with Canon EOS Digital Rebel XT