All around, threads of steam waft from hot pools in the crumbling volcanic rock, creating a generally postapocalyptic effect. The pools, some no larger than a manhole, simmer at more than 250 degrees, as a small sign politely alerts visitors. There are no fences, just a few cautionary ropes. You fall in and cook yourself, that's your problem. Barely as tall as an average person, these ponies are prized for their size and unique running gait.
Several farms offer guided pony rides.
Fortunately, it has nothing to do with that Brooke Shields movie. It's not even a true lagoon, but a man-made pool filled with hot effluent from the adjoining Svartsengi power plant, less than an hour from Reykjavik. So the water's not only clean and safe, but said to have therapeutic properties due to its high mineral content. It sounds icky, but it's really divine. Think of the best, most relaxing bath you've ever taken.