Y Garn (Glyderau)

Nant Clogwyn y Geifr (English: Devil's Appendix) is the tallest single-drop waterfall in Wales and one of the tallest in the United Kingdom. It is a plunge style waterfall located on the Clogwyn y Geifr cliffs beside Twll Du in Cwm Idwal, Snowdonia, Wales. It is formed where a small stream falls for approximately 305 feet (93 metres) to reach the slopes above Llyn Idwal. Depending on flow and the ambient temperature, it can be either an ice climbing route, a single drop waterfall, or a broken waterfall.

Foel-goch is a mountain in Snowdonia, north-west Wales, and forms part of the Glyderau range, in Gwynedd. It lies in between Y Garn and Mynydd Perfedd.Good views of Dyffryn Ogwen are seen with Pen yr Ole Wen, Carnedd Dafydd, Tryfan, Glyder Fawr and Elidir Fawr close by. Its height is 831 metres (2,726 ft).

Cwm Idwal is a cirque (or corrie) in the Glyderau range of mountains in northern Snowdonia, the national park in the mountainous region of North Wales. Its main interest is to hill walkers and rock climbers, but it is also of interest to geologists and naturalists, given its combination of altitude (relatively high in UK terms), aspect (north-facing) and terrain (mountainous and rocky). In a 2005 poll conducted by Radio Times, Cwm Idwal was ranked the 7th greatest natural wonder in Britain.

Llyn Idwal is a small lake (approximately 800 m by 300 m, or 28 acres) that lies within Cwm Idwal in the Glyderau mountains of Snowdonia.It is named after Prince Idwal Foel, a grandson of Rhodri Mawr, one of the ancient Kings of Wales. Legend states that the king's unfortunate offspring was murdered by being drowned in the lake. In fact Idwal Foel died in battle against the Saxons in 942 and an alternate version claims that he was cremated beside the lake, as was the burial custom for Celtic nobility. A number of small streams flow into Llyn Idwal from around Cwm Idwal. One small river flows out and joins the Afon Ogwen river at Pont Pen-y-Benglog near Ogwen Cottage, immediately above the Rhaeadr Ogwen waterfall.

Dinas Cromlech or Dinas y Gromlech is a distinctive rhyolite rock outcrop at the Llanberis Pass, in Snowdonia, northwest Wales, which has a distinctive "open book" shape that is clearly visible from the road (A4086), and is very popular for rock climbers, and features in the history of the sport.

The Glyderau (a Welsh plural form, also known in English as the Glyders) are a mountain group in Snowdonia, North Wales. The name derives from the highest peaks in the range, Glyder Fawr and Glyder Fach. According to Sir Ifor Williams, the word "Glyder" derives from the Welsh word "Cludair", meaning a heap of stones. The Glyderau stretch from Mynydd Llandegai to Capel Curig, and include five of Wales' fourteen or fifteen summits over 3000 feet; these include Tryfan, considered one of the finest mountains in Wales and one of the few mountains on the British mainland requiring scrambling to reach the summit. The eastern half of the range in particular, including Glyder Fawr, Glyder Fach and Tryfan, is very popular with walkers and climbers. Dinorwig Power Station, a hydroelectric pump-storage system, is located in a man-made cavern within Elidir Fawr. The slopes of the Glyderau also include the lake Llyn Idwal, and a number of classic climbing areas such as Rhiwiau Caws.

Mynydd Perfedd is a mountain in Snowdonia, Wales, forming part of the Glyderau. The summit has a shelter cairn, offering good views of Foel-goch's north-eastern face, and the Carneddau. Between it and Carnedd y Filiast, there are dramatic cliffs to the east, including the famous Llechen Cytrolar. To the south lies the parent peak Elidir Fawr, to the west Carnedd y Filiast and to the east Foel-goch and Y Garn. It is 812 metres (2,664 ft) high. The average annual temperature of the mountain is about 6 Celsius.

The Llanberis Pass (Welsh: Bwlch Llanberis; alternative English name, Pass of Llanberis) in Snowdonia carries the main road (A4086) from the south-east to Llanberis, over Pen-y-Pass, between the mountain ranges of the Glyderau and the Snowdon massif. At the bottom of the pass is the small village of Nant Peris.

The Nant Ffrancon Pass in Snowdonia, North Wales is at 312 metres (1,024 ft) at Pont Wern-gof, about one-third of a mile beyond the eastern end of Llyn Ogwen. The A5 road crosses it between Llyn Ogwen and Bethesda, Gwynedd

Marchlyn Mawr reservoir is a high level lake in Snowdonia behind Elidir Fawr mountain. It is used as the high level water source for Dinorwig power station, a closed-loop pumped storage hydroelectric generating facility. It is said that nearby lies the cave containing Arthur's treasure, a source of bedazzlement to the wanderer who sees it, and of disaster to the pilferer who touches it. The lake itself lies in between two mountains Carnedd y Fillast and Elidir Fawr and lies at a height of 636m above sea level and the reservoir took four years to build (from 1975 to 1979). The reservoir holds about 9.2 million cubic metres (320 million cubic feet) of water. From the reservoir, a 10.5-metre (34 ft) diameter tunnel runs for 1.7 km (1.1 miles) to a 10 m (33 ft) diameter vertical shaft. From the bottom of the shaft, a 9.45 m (31 ft) diameter tunnel leads to the power station, 670 metres (2,200 ft) away. It is possible to cycle up the road to the reservoir but a gate at the bottom prevents cars from driving on the road.

Ogwen Cottage Outdoor Pursuits Centre is situated beside Llyn Ogwen, in Gwynedd, Wales. It is owned by the National Trust, who bought the property at auction in October 2014 for £450,000. It was formerly for many years part of Birmingham City Council's Outdoor Learning Service, providing outdoor education, and with links to the climbing community.

Elidir Fawr is a mountain in Snowdonia, north Wales, the northernmost peak in the Glyderau. Its name means 'Big Elidir', named after a legendary warrior king of the 6th century also known as Eliffer Gosgorddfawr (Elidir of the Great Army).To the north of the summit is a small lake, Marchlyn Mawr, which is the upper reservoir for Dinorwig power station, a pump-storage power station hidden inside the mountain. Water from this lake flows through huge tunnels into the lower reservoir Llyn Peris. From the north, Elidir Fawr is very prominent, and can appear to be higher than the higher mountains behind it.