I remember seeing this Vallone dei Mulini (Valley of the Mills) while briefly crossing through Sorrento, Italy in July 2004. I remember being fascinated by it but not know what it was. I recently can across this story that explains that it was an old mill that ended up in this crevice due to an earthquake. I see that there are tours there. I would have really liked to tour this building. Maybe next time I am in the Amalfi coast???