Mark Engblom did a terrific series on the Fortress of Solitude last month so it's not my intention to cover that ground again. One thing I noticed when looking at the Fortress stories was that it's not a place of solitude at all. In fact, very quickly it became almost Grand Central Station, as Supes gave everybody the guided and unguided tour. In its first appearance, Batman slipped in:
In the next issue, it became home to millions of people, as Krypton's capital city was added (note however that the concept of this being an indoor place still hadn't been explained to Al Plastino, the artist):
Of course, Kandor had a huge role to play in the Silver Age Superman.
Lois gets a trip to the Fortress in Action #245:
In Action #247, a fake Ma and Pa Kent receive the red-carpet treatment:
Jimmy Olsen got his first visit to the Fortress in Superman's Pal, Jimmy Olsen #30 (August 1958):
In Action #261, everybody in Metropolis got to see the Fortress:
In a way, this seems to be the real purpose of the Fortress; not so much for Superman to get away from the pressures of the outside world, but a place for him to entertain visitors and guests.