This area is now a small park overlooking the River Lune, featuring a skatepark, but Green Ayre was once a core part of industrial Lancaster. The winch in the foreground commemorates a water-powered cotton mill and a dockyard which evolved into the town's main railway station. I presume the space itself was the goods yards & sidings.
Lancaster Priory and Castle are on the hill in the background. Greyhound Bridge, built in 1849 for the Midland Railway but converted to road in 1971-2, is visible next to the Millennium (cycle & pedestrian) Bridge, itself hidden by the tree on the right. The wall in the foreground is the approach to a third, Skerton (road) Bridge.