The Brecon Beacons National Park protects 519 square miles of upland terrain, yet its northern boundary lies just 40 miles from Cardiff Bay. Established in 1957, the park encompasses four distinct mountain ranges: Fforest Fawr, the Black Mountain, the central Beacons massif, and the Black Mountains to the east. Pen y Fan, the park's highest summit at 886 metres, draws 350,000 ascents annually, but the majority of its sandstone ridges and glacial valleys remain sparsely visited outside summer weekends. The landscape's defining feature is its horizontally bedded Old Red Sandstone, laid down 400 million years ago when this region lay beneath a vast tropical river delta. Erosion has carved the stone into flat-topped peaks and steep north-facing escarpments, while Ice Age glaciers hollowed the cwms—corrie basins—that now cradle dark mountain lakes. The Waterfall Country, centred on the Mellte, Hepste, and Nedd Fechan rivers in the park's southwest, exposes bands of limestone and millstone grit that create more than a dozen named cascades, including Sgwd yr Eira, where a path runs behind the curtain of falling water. Cultural layers deepen the terrain. Bronze Age cairns dot the ridgelines. Roman roads cross the high moorland, remnants of the garrisons that occupied South Wales for three centuries. Limestone caves beneath the Fforest Fawr contain some of Britain's longest subterranean passages, mapped to over 50 miles. The park's northern sector holds the Brecon Beacons National Park Visitor Centre at Libanus, open daily from 10:00 to 16:00 with no entrance fee, though parking requires payment. The building houses interpretation galleries on the geology, ecology, and human history of the uplands, and trails radiate from its car park toward Pen y Fan's southern approaches. Modern tourism infrastructure balances access with conservation. Designated Dark Sky Reserve status, awarded in 2013, protects the park's night skies from light pollution, making it one of fewer than 20 such reserves worldwide. Guided excursions from Cardiff typically cover 60 to 80 miles in a day, combining high moorland viewpoints, waterfall walks, and market-town stops in Brecon or Crickhowell, returning visitors to the capital by evening.