[Redbob]

"...Mt. Rushmore is an unfinished work."

Of course:
they ceased work when the sculptor, Gutzon Borglum, died.

Now, what MANY people don't know is that Ziolkowski was originally an assistant to Borglum

[Michael.SF.]

they ceased work when the sculptor, Gutzon Borglum, died.

Not quite correct. His son, Lincoln, continued to supervise the work for a short time after his father's death. It wa lack of funds that ended the construction.

Here is a picture of a model of how it was intended to look: