The term "white elephant" originated in Thailand (known as Siam at the time) where white elephants were highly prized because of their rarity and kept by the King as a status symbol. Elephants were so important to the country that a white elephant appeared on their flag until the early 20th century.
The phrase came to mean an object or endeavour which was high maintenance, costly, and served no real purpose. Like a tchotchke or a trophy spouse.