Guess what? San Francisco is changing. The city of today looks and feels less and less like the iterations of yesteryear. If Star Trek: Into Darkness has it right, tomorrow's version will resemble a bright, cheery Blade Runner, but with cable cars and a bionic Benedict Cumberbatch disturbing the peace. In the midst of tomorrow's world today, however, it's reassuring that, on the far western edge of this city of ours, rests a vestige of deep yesterday. Sutro Baths, often shrouded in a poignant fog, is a ruin within a bustling metropolis, the twisted rebar and algae-choked basins of what once was a thriving community hub, social center, ice rink, and vast repository of prior residents' childhood nostalgia. Now that's all gone. What remains is a place of repose in an increasingly frenetic realm. And, yes, it's free.