The western Beacons are dominated by the stark Black Mountain (Mynydd Du) range of hills that includes two glacial lakes at the foot of steep scarp slopes: Llyn y Fan Fach and Llyn y Fan Fawr. This wild upland wilderness contrasts with the rolling green fields below that create a patchwork across the steep sided valleys. Old native woodland and ancient, species-rich hedgerows break up this patchwork and provide hunting grounds for birds of prey such as the once rare red kite that you can now often see flying overhead.
This is a largely traditional agricultural landscape where age-old methods of management are still in evidence and many of the hedges are laid using traditional skills. There are also historical sites such as the striking 13th century Carreg Cennan Castle, four and a half miles south east of Llandelio, that sits atop a rocky escarpment overlooking the farming countryside below.
The Black Mountain (not to be confused with the Black Mountains in the east) is the range of unpopulated barren peaks that dominate the western part of the National Park. These can be a wild place where winds can get up, buffeting walkers trying to cross the many paths that offer some exhilarating walking. There is a strong feeling of getting away from it all when surrounded by this wild landscape with rocky outcrops and just a few trees clinging on to the more sheltered nooks and crannies. Being the highest point of this part of the Beacons it's the best place to get panoramic views across the countryside.
On the face of it this area might not seem good for wildlife but the different soil types over old red sandstone, millstone grit and limestone mean that there are a wide range of plants and habitats that attract other wildlife such as upland birds. The north and east facing cliffs of Bannau Sir Gaer and Bannau Brycheiniog support an interesting arctic-alpine flora, with species such as northern bedstraw, dwarf willow, lesser meadow-rue and roseroot, together with a rich moss and liverwort flora. Limestone grassland and low limestone pavement support lime-loving plants such as limestone bedstraw, limestone fern and common rock-rose. The northern cliffs support an important population of ring ouzels and birds of prey often hunt over the hills, particularly the red kite in winter.
The Great Forest (Fforest Fawr) area is not a forest as in trees, but is the range of mountains between the Black Mountain and the central Beacons that gets its name from when medieval royal hunting grounds were referred to as forests. Through this landscape upland streams flow into the Nedd, Hepste and Mellte Rivers that join the River Neath and eventually flow out into Swansea Bay. These streams and rivers cut through spectacular scenery of gorges, cliffs and waterfalls - the reason why it's called the "Waterfalls area".
Fforest Fawr is the centre of the UK's first European Geopark - a protected area for its geology - which promotes the understanding of the geology of the Brecon Beacons alongside sustainable tourism. The Geopark is made up of three main geological types: old red sandstone, limestone and millstone grit which give rise to stunning waterfalls and interesting cave systems. The varied geology produces a wide range of different plants and habitats ranging from species-poor, but no less interesting, upland moorland through to species-rich limestone habitats where you can find a greater diversity of species.
At the southern end of the western Beacons the Ystradfellte area with its lush wooded valleys in a classic limestone landscape is a total contrast to the barren mountains to the north. It is incredibly popular for walkers as there are many walks that take in the picturesque waterfalls common in this area.
The easier of the walks is the clearly signposted "Waterfall Walk" that takes you from the car park at Ystradfellte along the Afon Mellte. This leads you to two of the main falls, Sg d Clun-gwyn and Sg d Isaf Clun-gwyn passing Sgwd y Pannwr, a lower rocky fall, on the way. The walk's climax is the Sgwd Y Eira, Spout of Snow, that has a natural path behind the waterfall. For a different view of a waterfall you can walk along this path, but be careful as it can be slippy. Well worth the experience as you watch the curtain of water tumble over the rock above in front of you.
There are longer walks between Ystradfellte and Pontneddfechan that take in other falls such as Sgwd Gwladus, Lady Falls, on Afon Pyrddin and Horseshoe Falls and Sgwd Ddwli along the Afon Nedd Fechan. A mile south of Ystradfellte the River Mellte disappears into the mouth of Porth-yr-Ogof, White Horse Cave. This cave has the largest cave entrance in Wales - it is nearly 20 metres wide and 3 metres high. The cave entrance can be accessed just a few minutes walk from the car park, but it is a steep climb down the worn and uneven limestone so it might not be suitable for everyone. There are 3 kilometres of explored cave passages and it is a popular location for experienced cavers.
There are many sites of former iron age settlements. The finest iron age hillfort in the Beacons is undoubtedly Carn Goch in the foothills of the Black Mountain near Llangadog. It is one of the largest hillforts in Wales and covers 12 hectares of hillside. Its massive defences are easy to see in the shape of gateways, ditches and great mounds of stone rubble.