It's fascinating to follow the walking route that runs through the old gasworks in Gazi, in operation from 1862 until 1984. The preserved complex of furnaces and industrial buildings from the mid-19th century appear like giant art installations. Photos and interactive elements provide an idea of what the works were like when in operation. Make sure you go up the watchtower of the New Watergas building for a panoramic city view.
There's is also a pleasant cafe on-site as well as a kids' playground.
Note that the site is often used for music and other events.