Rio Tinto (Red River) is a unique area located in Southern Spain near the town of Huelva. It is One of the only places on earth where you feel like you might be on Mars. A 19th century train takes you through the otherworldly landscape, toward the river where the water flows like wine. (Or at least it looks like wine).
Mined since ancient times- mostly for copper- this river has a low oxygen and high iron content and is full of unusual microscopic organisms. Rio Tinto has captured the attention of NASA, and scientists have been sent to study the unique ecosystem that has apparent similarities to that of Mars and other planets in the Solar System.
Dive in HERE for more info on this unique river, and how you can get there to see it.
I like unusual things in our regular modern world, and this fits that category nicely.