Sugarloaf Mountain

Sugarloaf is made of very, very old rock.

Deep underground, heat and squeezing changed the rock. Later, rain slowly wore away the softer rock around it. The hard rock stayed standing tall.

Sugarloaf is made of a rock called augen gneiss. In Rio it is called the facoidal gneiss, from a Greek word meaning lens-shaped. About 560 million years ago, when great slabs of Earth's crust were crashing together, heat and pressure turned an older granite into this gneiss.

Much later, rain and warm weather slowly broke down the softer rock around it, which washed away. The tougher gneiss was left standing high. Cracks in the rock helped shape its steep walls, and pieces have fallen off over time.

The IUGS describes Sugarloaf as augen gneiss, locally the "Phacoid Gneiss" (from the Greek for lens-shaped), produced by metamorphism and deformation of a K-feldspar granite during the main collisional phase of the Ribeira orogenic belt about 560 million years ago (Ediacaran Period). Isoclinal folds are visible on its northern, southern and western faces.

Its shape comes from differential weathering. Under Rio's rainy tropical climate, the biotite-rich metasedimentary gneiss around it was preferentially weathered and eroded, leaving the fresher augen gneiss as high relief. Steep east-north-east fractures that affected the area in the Paleogene guided the erosion of the near-vertical north and south walls. A rock pillar still attached to the south wall, with a boulder deposit at its base, records past rockfalls.

A long time ago, an engineer had an idea. He wanted to build a road in the air.

Now cable cars carry people up. First they ride to the smaller hill. Then they ride all the way to the top of Sugarloaf.

In 1908 an engineer from the state of Rio de Janeiro, Augusto Ferreira Ramos, came up with the idea of an "aerial path" between the beach and the hills, National Geographic Brasil reports. Work began in 1910. The first section, from Praia Vermelha beach to the Morro da Urca, opened on October 27, 1912, and the final section to the top of Sugarloaf began running on January 18, 1913.

Today's cars carry up to 65 passengers each and reach the top in about three minutes. By 2023, the attraction had welcomed more than 50 million visitors from all over the world.

According to National Geographic Brasil, which cites Brazil's tourism ministry and Riotur, Augusto Ferreira Ramos conceived an aerial route between the hills and the beach in 1908 and founded the Companhia Caminho Aéreo Pão de Açúcar, the company that still ran it in 2023. Construction began in 1910; the Praia Vermelha–Morro da Urca section opened on October 27, 1912, and the section to the Sugarloaf summit on January 18, 1913.

The magazine calls the project very bold for its time and names two earlier passenger cableways, at Monte Ulía in Spain and the Wetterhorn in Switzerland. The modern cars carry up to 65 passengers to the 396 m summit in about three minutes, and more than 50 million people had visited by 2023.

Green forest grows on the hills around Sugarloaf.

Small monkeys called marmosets live there, and birds too. All around is the big city of Rio.

The bare rock of Sugarloaf rises above greener hills. The IUGS explains that the forested areas grow on a different gneiss that weathers more easily. On the hills there is an ecological park where visitors can see marmosets, small monkeys, and birds.

Sugarloaf is also part of a city. UNESCO describes Rio's mountains, forests, bay and beaches as one great landscape shaped by people and nature together, with Sugarloaf as one of the peaks that frame Guanabara Bay. Building is limited around it: UNESCO reports that nothing may be built higher than 60 meters above sea level in the surroundings of Sugarloaf and Urca.

The IUGS notes that the forested areas around the monolith grow on the biotite-rich metasedimentary gneiss, which weathers more readily than the bare augen gneiss above. National Geographic Brasil mentions an ecological park on the hills where visitors can see marmosets (saguis) and birds.

UNESCO's World Heritage listing treats Rio as an urban landscape shaped between mountain and sea, with Sugar Loaf, Urca, Cara de Cão and Corcovado framing Guanabara Bay. Planning rules adopted in the 1970s and sanctioned in 1976 forbid construction above 60 m above sea level in the surroundings of Sugar Loaf and Urca, and above 100 m on the city's other hills, which are considered forest reserve.

Visitors ride the cable car to the top.

Hold on to a grown-up's hand at the lookout. Stay behind the railings. Only trained climbers go up the steep rock walls.

The easy way up is the cable car from Praia Vermelha, in the neighborhood of Urca, which stops at the Morro da Urca before the final ride to the summit. The park's lookouts show Botafogo cove, Praia Vermelha, the Copacabana shoreline and part of Guanabara Bay.

The IUGS notes that the walls can also be climbed, but only by difficult routes, so climbing is for trained climbers with proper gear. At the lookouts, stay behind the railings and keep a close eye on younger children.

Access is by the two-stage cable car from Praia Vermelha via Morro da Urca to the summit; the IUGS notes that the summit can also be reached by difficult climbing routes, which are for trained, equipped climbers only. National Geographic Brasil lists the views from the lookouts: Botafogo cove, Praia Vermelha, the Copacabana shoreline and part of Guanabara Bay.

The monolith itself is protected: UNESCO records it as a national monument and part of the World Heritage property, with height limits on nearby buildings. The IUGS's description of past rockfalls on the south wall is a reminder that steep rock faces change. Visitors should stay on paths and behind railings.