At over 90,000 square feet, this former warehouse-turned-museum is one of the largest galleries in the world devoted exclusively to photography and video. But even with this amount of space, the main worry here seems to be that it will get too crowded. So, in an eccentric move (hey, this is San Francisco, after all), the Pilara Foundation, which owns the institution, allows only 20 people in at a time. That means if you don’t make advance reservations online, you might not get a place during one of the 2-hour visiting slots (entry is free). And that would be a shame, because its exhibits tend to be dazzling. In the past, they’ve featured iconic works by Diane Arbus, Man Ray, and Walker Evans—though you might never know those were the photographers: in an attempt to make the viewers’ experience of the art more immediate and unfettered, the gallery posts no wall text whatsoever. Instead viewers can borrow a rather loosely organized gallery guide to lead them through the mazelike space. It’s rather like an art scavenger hunt.