Brain Game: Even Faster!

Today's Brain Game is a poem wot I writ myself. I know, don't quit my day job. (But this is my day job.) Good luck!

They're America's favorite rock group A quartet with notable flair One wears a beard, one specs and a 'stache, And the other two love their long hair You can see them in person near Keystone Although none of them are still alive The four of them have been together Since nineteen and, oh, twenty-five.

Here is the ANSWER.

THE SOLUTION:

Mount Rushmore.