On the way to Hoi An, five hills of marble and limestone make up the Marble Mountains. Only one, Thuy Son, is open to visitors. An elevator leads up to a pagoda, but that’s not all there is. Paths connect temples and caves, where we sought refuge from the rain. As the elevator was closed because of the weather, we took hundreds of steps back to ground level, thankful not to be drenched by the downpour.