Roque Nublo is a monolith

Monolith

A monolith is a geological feature such as a mountain, consisting of a single massive stone or rock, or a single piece of rock placed as, or within, a monument...

 feature that is 80 m tall. It is one of the most famous landmarks on the island of Gran Canaria

Gran Canaria

Gran Canaria is the second most populous island of the Canary Islands, with a population of 838,397 which constitutes approximately 40% of the population of the archipelago...

. The elevation is 1,813 m ranking it second on the island and one of the tallest in the archipelago. It is municipally located in Tejeda

Tejeda

Tejeda is a Canarian municipality in the westcentral and the central portion of the island of Gran Canaria in the Las Palmas province in the Canary Islands. Tejeda is the main city of Cumbre and is the second smallest village on the island as well as the highest municipal seat on the island. The...

 a few kilometres from the town centre. It was formed by a volcanic eruption around 4.5 million years ago.
It can be reached very easily by a nearby parking lot by a hike of some 30min. Thus, especially in summer you'll encounter quite a lot of tourists up there. But you'll also find a lot of hikers and quite some climbers and the tableau del Nublo is an interesting location if you want to watch the climbers in their 1h ascent. Views from Roque Nublo are Mount Teide (Teneriefe)the 3rd largest volcano, and the highest point in Spain,
El Fraile, a rock statue of a Monk praying down, Pico de la nieves the highest point on the islands, but can not be accessible everyday but there is a platform underneath it. Transport to Roque Nublo can be The Las Palmas bus, a rented car, helicopter tours and other modes of transport.
Gran canaria