A volcanic plug, also called a volcanic neck, is a volcanic landform created when magma hardens within a vent on an active volcano. A natural monolith is a mountain or large rock formation consisting of a single massive stone. Both types of these geological structures are similar in that they are often steeply rising above the surrounding terrain. The unusual appearance and the buildings which are often located on these structures, amaze visitors and attract them to come back again.
# Saint Michel d'Aiguilhe, FranceThe Chapel of Saint-Michel d'Aiguilhe is a fascinating little pilgrimage chapel perched atop a rocky needle of volcanic formation jutting dramatically high into the sky, at a place near Le Puy-en-Velay in France. The basalt needle on which the chapel is built rises approximately 280 feet (85 m), and is reached by 268 stone steps that wind their way up the side of the rock. The chapel is surrounded by a walkway that provides a beautiful view of the city with its Puy Notre Dame Cathedral and the old bridge crossing the cusps terminal.
# El Peñón de Guatapé, ColombiaEl Peñón de Guatapé is a monolithic formation located at the town and municipality of Guatapé, 1 km (0.6 mi) inside the city limits in Antioquia department, Colombia. The rock was first climbed officially on July 1954. In 2006, Luis Villegas, Pedro Nel Ramírez and Ramón Díaz climbed the rock in a five-day endeavor, using sticks that were fixed against the rock's wall. A new species of plant was found on the top of the rock, subsequently named Pitcairma heterophila by a German scientist.
# Trosky Castle, Czech RepublicTrosky Castle is a castle ruin located some 10 km (6 mi) south of Semily, Liberec Region, Czech Republic. It is one of the most famous Czech castles and is situated on the summits of two basalt volcanic plugs. On the lower peak (47m or 155ft) is the two-storey structure called Baba (Old Woman), and on the higher outcrop (57m or 187ft) is the four-sided structure known as Panna (Virgin). The castle is a landmark which cannot be missed in the countryside known as Český ráj (Bohemian Paradise).
# Katskhi Pillar, GeorgiaThe Katskhi pillar is a natural limestone monolith located at the village of Katskhi in western Georgian region of Imereti, near the town of Chiatura. It is approximately 40 metres (130 ft) high, and overlooks the small river valley of Katskhura, a right affluent of the Q'virila. The rock, with visible church ruins on its top surface of around 150 sq m (1,600 sq ft), has been venerated by locals as the Pillar of Life. It remained unclimbed by researchers and unsurveyed until 1944 and was more systematically studied from 1999 to 2009. These studies revealed the early medieval hermitage, dating from the 9th or 10th century.
# Zuma Rock, NigeriaZuma Rock is a large monolith located in Niger State, Nigeria. It is just north of Nigeria's capital Abuja, along the main road from Abuja to Kaduna, and is sometimes referred to as Gateway to Abuja. It is depicted on the 100 naira bill (national currency). Zuma Rock is 725 m (2,400 ft) above its surroundings. As the tourist gets closer, a human like face becomes visible with engravings representing the eye sockets, the nose and the mouth on the side of the rock that faces the Abuja - Kaduna express road. Zuma Rock represents a beautiful and unique natural work of rock formation. If offers a good environment for picnicking and relaxation. A Five Star Hotel, Zuma Rock Resort International Limited is being constructed near the rock.
# Sugarloaf Mountain, BrazilSugarloaf Mountain, is a peak situated in Rio de Janeiro, Brazil, at the mouth of Guanabara Bay on a peninsula that sticks out into the Atlantic Ocean. Rising 396 metres (1,299 ft) above the harbor, its name is said to refer to its resemblance to the traditional shape of concentrated refined loaf sugar. The mountain is only one of several monolithic morros (hills) of granite and quartz that rise straight from the water's edge around Rio de Janeiro. A glass-walled cable car, capable of holding 65 passengers, runs along a 1400-metre route (4,600 ft) between the peaks of Pão de Açúcar and Morro da Urca every 20 minutes.