Head to the Stadium of Light—home of the Sunderland Football Club—and you’ll see a series of striking sculptures standing within the park. There, four eight-foot-tall steel men roll giant lumps of coal up the riverbank in a poignant tribute to the city’s industrial past.

The Steel Men Of Wearside were initially commissioned by the Regional Development Agency, One NorthEast back in 2001. They were installed as part of a plan to transform the site of the former Wearmouth Colliery.

The initial plan was to pay homage to the men of Wearside who used to work in the various coal mines around the River Wear. The sculptures also helped to decorate the area that is also one of the last stretches of England’s coast-to-coast bicycle route.

Although they were initially visible from multiple locations around the river, the trees and bushes have been left to grow as they please. Nature’s mission to slowly reclaim the riverbank has thus limited the places you can view the steel sculptures, making them feel a bit like a hidden secret.