Why were Belle Époque cities beautiful?

As a kid growing up in the Bay Area, I often visited San Francisco’s Exploratorium science museum. Back in the 90s and 2000s, it was housed in what I still think is one of the most beautiful buildings in the United States: the Palace of Fine Arts. In my memory, it stands out as a fairy-tale like space that never felt entirely real.

It was never clear to me, when I was eight or nine, just how old the buildings of the complex were. But there was a palpable feeling of otherworldliness to them. We historians love to say that “the past is a foreign country.” These buildings felt like visiting that foreign space of the past.

Much later, it occurred to me that the buildings — the rebuilt remnants from the 1915 Panama-Pacific International Exposition, a World’s Fair designed to celebrate the op…