Kinti Well (Ķintu aka)

Very unknown even for locals, but actually it's one of the most unique and mysterious man-made monuments in Latvia. It's at least 200 years old (but could be much older) well which is made of enormous stone blocks - largest of them weighs more than a ton each. The scientists haven't explained how the well was made (how it was possible to move around and process so large stones), who, when and why did it.