By Martin Rand III, CNN

(CNN) - Lakota warrior Crazy Horse has long been a controversial figure, so perhaps it's apropos that his memorial follow suit.

Though he's best known for fighting against George Armstrong Custer at the Battle of the Little Big Horn, Crazy Horse led his tribe numerous times against settlers and miners in the Dakotas, Montana and Wyoming and elsewhere before his 1877 death at Nebraska's Fort Robinson.

But forget his disputed role in that battle or the claims that he's never been photographed or the conflicting tales of how he met his end - the real mystery is more contemporary: When is the sculpture in his honor going to be complete?

In the mountains of Black Hills, South Dakota, rests the Crazy Horse Memorial. It pays tribute to the Native American war hero with a sculpture that, at many times the size of nearby Mount Rushmore, will one day constitute the world's largest mountain carving.

That is, if it ever gets completed.