A two-hundred-metre-long earthwork sculpture in the shape of a recumbent horse, carved into the reclaimed spoil tips of the old Penallta colliery about 7 km north of Caerphilly. From the ground it's hard to read; from the air or from the surrounding paths along the hilltop the form resolves into a perfect figure of a pit pony at rest. The sculpture is made of stone-filled gabions and is the largest of its kind in the United Kingdom.
The surrounding Parc Penallta is a pleasant 100-hectare country park with marked walks, a wooded ridge, ponds in the bottom of the old workings, and several other public artworks. Free, open all hours, and a good place to bring children. Best read together with the small heritage display at the visitor centre, which explains what the valleys were like before the pits closed.