The Sierra Negra (Black Mountain) volcano on Isabela Island in the Galapagos is an active shield volcano. Its most recent eruption was in 2018. With a 10 kilometer diameter, it has one of the world’s largest craters. It is the only volcano in the Galapagos that visitors are able to descend into and hike as part of a tour with a nature guide, so I decided to give it a try.

First we walked from the top of the crater down into the caldera, then across the bottom of the crater to the other side. Then climbed up again to the other side, to view the sulfur mines, and descended back down to the bottom. And finally, climbed back up to the top. The whole trek took about 5 hours.

During the hike, the landscape changed from lush green ferns, to coal-black volcanic rock, to white calcium deposits and yellow sulfur.

At the top of the caldera are fumaroles and sulfur mines. The mines are no longer used for sulfur extraction, but continue to acively emit gases. The golden-yellow sulfur made for some picturesque sights. My birding lens came in handy for these closeups!

The hike down into the crater was easy-peasy. The walk back up, not so much. When I’m on level terrain, for the most part I can walk for miles and keep up with a tour group. But throw in a hill, and my pace slows down to a crawl, with frequent water stops in the intense heat. I’m grateful that I still have the stamina to hike a mountain, but it’s been frustrating to always be the last person up that mountain! The only reason I wasn’t last on this hike was because there was a family with three young children in our group. One of the kids fell and skinned a knee, so that slowed them down a bit. Otherwise, they would have lapped me too!