Musée de Minéralogie at the École des Mines, : Paris, France

One drizzly March morning in Paris, I found myself trying to find the Museum of Minerals at the School of Mines. I passed a glassed vestibule watched by a friendly guard and wandered through austere school halls marked with noticeboards, then turned a corner and found myself facing a startlingly grand staircase surrounded by murals depicting ice caves and other geologically sublime places. Up the marble stairs was a locked door; I rang the bell and bought a ticket.

Inside, there were collections of opals and meteorites; rocks that looked like images of lost cities and others as round and puffed as clouds. My favorite was a display of beryls labeled "Confusions."

Everything was held in beautiful blond wood cases, some with slanted glass tops, some protected by lids, that stretched on from room to room to room. Tall windows overlooking the Jardins du Luxembourg were thrown open and the rooms smelled of rocks, rain, and wood; I caught glimpses of the Eiffel Tower behind a scrim of cloud. 

As I was leaving, I found a locked door—through its glass pane, I could just see a peek of the skylit library, but it was closed that day.