'Greenheart' is one of five sculptures that were commissioned by the Great North Forest. Artist William Pym was selected to design a scheme to link the five sites through sculpture. The sites – Watergate, Monkton, Herrington, Rainton Meadows and Hetton Lyons – are all linked by their shared past as reclaimed landscapes that used to be involved with mining and the processing of coal and in the future as accessible green spaces. The artist proposed five similar sculptures for each of the five sites. Each sculpture takes the same form, a walk-through structure located on or close to existing paths. The sculptures are made from weathering steel and linked by two lines or rails of steel, representing the paths and railways. Each sculpture incorporates a planting scheme of shrubs or trees, to contrast with and sometimes grow through and over the works.