Amble out to the end of Basin Rd, a beautiful 1-mile walk from the north end of Gastineau Ave, to the former Alaska-Juneau Gold Mining Company complex. It's now a museum where you can view remains of the compressor house and examine tools of what was once the world’s largest hard-rock gold mine.
There is also a re-created mining tunnel and a 3-D glass map of shafts that shows just how large it was. Nearby is the Perseverance Trail, and combining the museum with a hike to more mining ruins is a great way to spend an afternoon.