Best for geology

 
Sgŵd Gwladus
This beautiful 10m waterfall is the cascading climax of the Sgŵd Gwladus walk. Set in a shady natural amphitheatre, it was formed as torrents of meltwater from the last Ice Age carved out the area’s rocky gorges.
 
Dan yr Ogof
With vast subterranean chambers, winding passages and delicate stalagmites and stalactites, the National Showcaves Centre for Wales is a real rock star. Check it out while walking the Craig-y-Nos Circular.
 
Craig Cerrig-Gleisiad
Both the Glyn Tarrell Geotrail and the Storey Arms to Visitor Centre walk take in the spectacular 150m-high cliffs of Craig Cerrig-Gleisiad. Carved out by glaciers during the last Ice Age, these atmospheric crags are among the National Park’s most compelling features.
 
Cwm Llwch
The deep hollow beneath Corn Du is another of the National Park’s many classic geological features. Scooped out by the grinding of giant ice sheets, it can be seen as you tackle the Beacons Circuit.