White lions are leucistic, not albino - they are not totally devoid of pigmentation. Instead of the red eyes seen in albinos, they have blue or yellow eyes. They also sport black nose tips and dark patches behind their ears. Due to an uncommon gene mutation, their light tawny or off-white coat is a few shades lighter than that of the common lion.
They were heavily sought after by circuses and hunted as trophies and became technically extinct in the wild in the early 1990s.