Route: Taff Trail (United Kingdom)

The Taff Trail is a 55 mile (88 km) cycle and walking route starting in the south in Cardiff Bay and travelling north to Brecon Theatre. It is made up of old railway paths, forest paths, and canals and follows National Cycle Route 8. 

For the first 50km or so from Cardiff Bay there is a gradual incline. Once you reach Merthyr Tydfil you'll notice a steeper ascent all the way up to Pontsticill. Some slight respite from the climb is experienced around Abercynafon before the final push up to Talybont Reservoir which is the highest point of the Taff Trail. Some of the best views in Wales can be had here before the sharp decline down through Llanfrynach and on to the final destination, Brecon.

From mytafftrail.co.uk