Start: The old pump house, Lower Neuadd Reservoir  Foot: The Beacons Way and the Taff Trail pass close by.  Cycle: National Cycle Network Route 8-Lon Las Cymru and the Taff trail pass close by from Brecon and also from Talybont-on-Usk to the east and Cardiff from the South. The infamous Gap road passes close by and can be joined from the trail at Torpantau. See www.sustrans.org.uk. Beacons Bus carries bikes over the summer from Cardiff to Brecon.  Train: Merthyr Tydfil (12 miles/19 kms), Abergavenny (48km/30 miles), then catch X43 bus.  Buses: X43 by Sixty Sixty, Cardiff – Abergavenny. Alight at Storey Arms. See www.transportdirct.info  Road: Alongside the A470 Brecon to Cardiff (8 miles/12 kms from Brecon) and from the A40 Brecon to Abergavenny road, using country lanes to access the site.  Nine miles, about four hours. A difficult upland walk, this area is notorious for its rapidly changing and severe weather. Sturdy boots, warm clothing and good waterproofs are essential, as are an OS map and compass. Dogs are welcome but please keep them on a lead and control them around livestock.  Keep an eye out for these ancient cairns, which are approximately 5,000 years old and located at the summit of Pen y Fan and Corn du. When the cairns were excavated, archaeologists found Bronze Age turf that was still green and perfectly-preserved heath bed straw in flower, so we know that the cairns were built in early summer.  Llyn Cwm Llwch is a wonderful example of an upland glacial moraine. This important glacial landscape gives us fossil evidence of the first land plants. The Site of Special Scientific Interest (SSSI) designation for the Central Beacons focuses on the communities of arctic-alpine plants found here, in addition to the important geology of the area. Further down the valley you can see evidence of an old army firing range, which gives you an idea of the variety of ways this landscape has been used over the years.  This is the highest point in the southern UK and it is easy to see how the pressures of its popularity have taken their toll; the patchwork quilt of intensive agriculture appears thrown out onto the landscape, the matrix of hedgerows acting like seams fixing one field to the next. On a good day the panoramic view gives a great insight into the way we use the land and the impact we have on it.  1. From your starting point at the old pump house, make your way to the left of the reservoir, through a gate and start to ascend the steep climb onto the Craig Fan Ddu ridge.  2. Once you have got your breath back, turn right and follow the ridge around towards Corn Du. Looking to your right you start to get a sense of the sheer scale and beauty of the glacial valleys.  3. As you approach Corn Du, the path forks – right will take you around to Pen y Fan or left takes you up over the second highest peak in the Beacons (873m). Take the left fork here. As you make your way towards the Bronze Age burial cairn, look to your left for views of Y Gyrn, Fan Fawr, Mynydd Du and in the far distance the Carmarthen Fans.  4. Continuing around the crest of Corn Du, drop down into the saddle and up onto Pen y Fan. From Pen y Fan there is a steep descent off the summit until you get onto a stone pitched path that takes you down Craig Cwm Sere and up the steep climb to the summit of Cribyn. Looking back you can see the near vertical north face of Pen y Fan which falls away into the Cwm Sere valley.  5. At the Cairn turn right and follow the ridge along the back of Cribyn. Some sections along this path are fairly boggy where the peat has been exposed and has started to erode. This is evident in a number of places around the Beacons. Carry on down until you come to the gap road. This was the first track to enable horse drawn carriages to cross the mountain range; it is thought to be a Roman road, although no archaeological evidence has been found to prove this.  6. Crossing the track you leave National Trust land over the style and follow the fairly steep path to the summit of Fan y Big. This is a great vantage point to stop and admire the route you have taken.  7. From Fan y Big, follow the Craig Cwm Oergwm ridge heading back towards the Neuadd Reservoir. As the ridge arcs around to the left, split from the path and head straight on making your way diagonally down towards the lower Neuadd reservoir.  8. Coming back onto the gap road and through the metal gate you follow the tarmac road back round to the pump house and the car park where you started.
This challenging but rewarding walk, provided by the National Trust, covers   the best of the Brecon Beacons and is one of the top ridge walks in Britain.