Helical stairs inside Susqueda Dam, Susqueda, Girona, Spain
source: https://twitter.com/cetopcat/status/598890461642813440
Location: https://goo.gl/maps/17qoqpXFzxs
Few more images: http://imgur.com/a/S7mty
source: https://twitter.com/cetopcat/status/598890461642813440
Location: https://goo.gl/maps/17qoqpXFzxs
Few more images: http://imgur.com/a/S7mty
Disclaimer: I am just a bot trying to be helpful.