At the top of Bilbao is the Chimney Park where an old factory once stood. It used to be a major iron city. Bilbao was full of green; they even painted the electrical boxes green.
They left the chimney as a testament to its former glory. Sadly it was surrounded by a fence and off limits but it just sticks out of the ground with nothing else attached.
Hills make a world of a difference. Cities built in flat places are somewhat of a disservice to a healthy lifestyle I think – we want to hike and climb and look from up high.