ALSO on the subject of hot springs, let me tell you all about Furnas, a town built in the caldera of an active volcano, which erupted less than 400 years ago. 

Furnas is on the little island of São Miguel is one of the Azores (a Portuguese island chain), which are located here: 

the portuguese, probably: uninhabited islands about as far from anywhere as you can get in the atlantic ocean, still steaming slightly with geologic newness, and so loosely formed that whole hillsides regularly just slide into the sea? sounds perfect! we’re gonna settle the shit out of this place. bring the cows.

The whole island chain is just the tops of a bunch of volcanoes right where the North American Plate, the Eurasian Plate, and the African Plate collide, so it is, as one might imagine, full of geology that is more, uh, excitingly interactive than average. Furnas is especially exciting, because it is, as the name (”furnace”) suggests, built smack-dab in the middle of a caldera that erupted as recently as 1630. (As the islands were first settled in 1432, yes, they damn well knew what they were getting into here.)  Please enjoy this interactive map of the amount of earthquakes this town gets on a regular basis. 

To start out with, the Lagoa do Furnas is a caldera lake that is eerily green, due to being… basically one giant hot spring. Because it has such a large surface area, it isn’t actually hot for the most part, but the geothermal heating system just below the lake keeps it warm enough that algae have a fucking field day. When I visited it was a bizarre yellow-green looking like pea soup, but it gets bluer during the winter as it cools somewhat, and when the algae blooms die off.

Yum.

Beside the lake is an area of mudpots, which have claimed the lives of many idiots who got too close. When I went in 2013 I was told that after the most recent death they’d actually decided to put up fencing, which was loosely constructed and made of bamboo. Well, provided no one like… leans on it… I’m sure it’ll be fine. Probably. 

My panorama of the lake shore: to the left, mudpots and fumaroles (featuring the world’s flimsiest safety railings), to the right, the unearthly yellow lake. Foreground: the craziest fucking cooking method ever. (full size image here)

So what do the citizens of Furnas do with this area of geothermal heat leaking from beneath the earth’s crust? Cooking! The local specialty is cozido, which is basically what you get when you decide to have your clambake in a goddamn volcano. But unlike a clambake, no need for hot rocks- the ground comes pre-heated. This video shows the pre-dug holes, and some dudes putting the pots in and removing them. There are several local restaurants that specialize in this and have designated holes, the rest are just free to use- show up with your pot, and someone will help you load it in and then be like “come back in six hours, bye.” We were staying with a family friend in nearby Povoção, and she sent us to the lake with a loaded pot (contents: a mix of chouriço, potatoes, cabbage, and various other meats and root vegetables). It was… just as you expect a pot full of boiled sausage, potatoes, and cabbage to taste like, tbh, but it was worth it for the method of cooking. 

And then there’s the town: a charming little hamlet forever on the verge of being cooked. Wikipedia captions this lovely image of the town “the geologically active region of the Furnas valley.”  The highlight is obviously hot springs that are cooled down enough by running through a stream for a bit that you can safely get into them without being boiled. Poça do Dona Beija is fantastic and also… colorful:

yes, that’s natural, and yes, that stains. 

Those hot springs are cool enough to get into without dying. There are others in the town that are just left to themselves, and are definitely not. Basically, if you see water in Furnas, there is a greater than 50% chance of being boiled like a cozido if you hop in. There are also multiple “healing” springs, some of which, just hanging out by the sidewalk of a busy road, are labeled individually, according to which ailment they “cure”, and can be used by either drinking them, or running the water over the affected body part. According to my mother, it tastes terrible- which is, of course, because of the sulphur. 

Which brings us to another Fun Fact about this ridiculous place: the entire town- in fact, most of the valley- smells strongly of sulphur, all the time. It’s like living near a paper mill, except the wind never changes and gives you some relief, because it’s coming from all directions. It’s worst by the fumaroles and mudpots, but that’s just relatively speaking. According to residents, you just stop noticing it after awhile. 

The absolutely best Furnas anecdote I picked up is that recently, some out-of-towner developers bought up what had been open farmland on a side of town that no one had built on in the hundreds of years prior. They built a series of fancy new houses… which are now nearly all uninhabitable, due to geysers and/or fumaroles opening in the basements. The houses are still just there, standing empty as a testament to the hubris either a) of not asking the locals why they have avoided building in an area for hundreds of years or b) of building your town on an active volcano.