A short drive south of Rincón, near San Antero, there is a small mud volcano — a conical hill about ten metres high with a crater that bubbles up a thick, grey, mineral-rich slurry. You climb a wooden ladder up the outside, drop into the bath, and float on your back in mud so dense you cannot sink. Locals smear themselves head to toe. There is a freshwater wash-off at the base of the cone, run by the women's cooperative that maintains the site.
Several mud volcanoes are scattered across this part of Colombia's Caribbean lowlands. The more famous Totumo, near Cartagena, gets the tour buses — but the smaller volcanoes near San Antero and Galerazamba are calmer and easier to combine with a Rincón base. Half-day trip with a hired taxi.