Visible from the highway on the prominent east-west ridgeline across the river and south of park HQ are two large black squares. Out of all geologic context, deposited high on a ridgetop, are two house-sized cubes of good, hard black rock that offer an afternoon's worth of climbing in a spectacular setting - on a clear day you can see from Denali to Mt. Hayes. Wow!
Easy topouts on the small boulder to scary highballs on the big 'un.
Getting there is the crux! Bring gaiters, a mosquito head-net and be prepared to wade/rock-hop a river and get in a good alder-bash.
Finish the ridgewalk up the peak to the West and pick a draw to head back to the road for a great circle trip, about 12-14 hours. One of the best outings of my life.
Watch out for bears and moose!