A white elephant is an idiom for a valuable but burdensome possession of which its owner cannot dispose and whose cost (particularly cost of upkeep) is out of proportion to its usefulness or worth. The term derives from the story that the kings of Siam (now Thailand) were accustomed to make a present of one of these animals to courtiers who had rendered themselves obnoxious, in order to ruin the recipient by the cost of its maintenance. In modern usage, it is an object, scheme, business venture, facility, etc., considered to be without use or value. Also Albino elephants exist in nature, usually being a reddish-brown or pink color.
Contributions by N328KF, Ckatz, and Nick-D.