The history of the hillside cuts in Rio de Janeiro is closely tied to the city's growth and modernization throughout the 19th and 20th centuries, when technology already allowed, with greater force and ease, the opening of tunnels, passage cuts, and the use of quarries to enable traffic flow and urban expansion. The hills, which are natural features of Rio de Janeiro's geomorphology, with their steep slopes and rocky formations, have always represented both an obstacle from a construction standpoint and an opportunity for the use of borrowed materials.
In the early 19th century, Rio de Janeiro began to undergo a more intense urbanization process, especially with the arrival of the Portuguese royal family in 1808. However, the limitations imposed by the hills, which fragmented the city and made communication between different areas difficult, were one of the main challenges to urban growth. It was in this context that the first efforts emerged to cut through or level hills and build passageways, with the aim of improving access and circulation between Downtown and the suburban areas (recalling that Zona Sul falls into this category of suburb).
The demolition of Morro do Senado, already at the end of the 19th century, would mark the urbanization model that would lead the transition to the republican model of society. In 1879, the leveling of the hill was authorized, so that its materials could be used for the landfilling of Saco de São Diogo (present-day Canal do Mangue), marshes, and lagoons in the region of Central do Brasil and the port area, making room for the opening of today's Praça da Cruz Vermelha. This work lasted more than 20 years, and the volume of material was responsible for paving the way from Cidade Nova to the port area via Avenidas Rodrigues Alves and Francisco Bicalho.
Technology advances, and the first drilling into the massif for the construction of a tunnel takes place to connect the neighborhoods of Rio Comprido and Laranjeiras, known as the Túnel da Rua Alice. The start of its construction dates back to 1886, still in the 19th century, intended for the passage of trams running the lines between the neighborhoods. Following this, the passage tunnel to the wild Praia de Copacabana takes advantage of the narrowing between the Morro da Saudade and Morro São João hills for the opening of the Túnel Velho (Alaor Prata). The flow of trams directed toward the timid seaside plain substantially helps promote real estate speculation in the neighborhood, then still being discovered. Its nickname caught on after the construction of the Túnel Novo (Túnel do Leme), already in the early years of the following century. This tunnel, in turn, drilled through the lowered ridge connecting the Morro de São João and Morro da Babilônia hills, shortening the route between the cove of Praia da Saudade (today the Iate Clube do Brasil) and Praia do Leme, the first "open sea" beach to become a focus of urban expansion. The years that follow establish Praia de Copacabana as the little princess of the sea, exporting Carioca culture and identity to the world. The Copacabana Palace is, without doubt, the expression materialized in space of the vigor with which the society of that time valued this site.
Returning to the region of Central do Brasil and the port zone, in 1919, a small Tunnel was built, named João Ricardo, advancing beneath Morro da Providência, shortening the path between Campo de Santana and the Port. The technological power favoring the destruction of Rio's rocky massifs gained strength with industrialization and the needs of locomotion; faced with the city's rugged terrain, the economic interests of contractors and real estate developers converged with a state power driving the ceaseless works of a geological nature. As an icon of urban intervention, with an almost tectonic display of force, the Demolition of Morro do Castelo, in the 1920s, marked history as a great project of modification of Rio's urban geography, paving the way for the construction of new avenues and facilitating the city's expansion. Morro do Castelo, which had once housed the center of the city's occupation, was demolished to make way for Avenida Central and Praça XV de Novembro, with the goal of facilitating the circulation of winds in the city, opening up to a greater flow of vehicles, and taking the opportunity to fill in more flooded areas and give the city the air of modern, hygienist urbanity, at a time when it was the modern and recently republican tropical capital of Brazil. This demolition meant the loss of one of the city's most important historical landmarks, but it also marked a decisive shift in Rio's modernization.
Right after that, also striking is the cutting of Morro de Santo Antônio, carried out in 1950, down to almost half of its rocky mass, preserving only the Monastery of Santo Antônio and the Church of the Ordem Terceira de São Francisco. The work expands Largo da Carioca, which, before the occupation, was home to the lagoon of the same name, and makes clear modern architecture's intent toward broad vistas and esplanades. In this case, the connection with Praça da Cinelândia (Praça Marechal Floriano Peixoto) reinforces the symbol of republican civility, with its urban facilities worthy of a secular society with balanced powers, amid full cultural richness and technological currency: the Theater, the Library, movie theaters, the Senate, the Chamber of Deputies, and the Supreme Federal Court.
However, it is from the second half of the 20th century onward that Rio de Janeiro underwent a more aggressive process of modifying its hills, especially for the construction of tunnels and passage cuts that would connect the city's different zones. In the late 1940s, from Praia do Flamengo to the South Zone, starting with the Túnel do Pasmado, easing the passage from Botafogo to Praia da Saudade, joining up with Avenida Lauro Sodré and Avenida Princesa Isabel toward Copacabana. In this neighborhood, in the following decades, two tunnels are bored through the foothills of the surrounding hills: Túnel Sá Freire Alvim and Túnel Major Rubem Vaz, connecting, respectively, Rua Tonelero to Rua Pompeu Loureiro, beneath Morro dos Cabritos, and Rua Barata Ribeiro to Rua Raul Pompéia, beneath Morro do Cantagalo.
From 1950 onward, large tunnels would be excavated and opened, connecting the city's neighborhoods underground. The André and Antônio Rebouças Tunnels (Rebouças Tunnel), opened in 1950, and the Santa Bárbara Tunnel, in the 1960s, were fundamental to the city's road infrastructure, enabling faster traffic flow (nowadays, not so fast at certain rush hours) and shortening distances across rugged topography. The eastern tip of the Serra da Carioca is bored through at two points there: under Morro da Coroa, in the Santa Teresa neighborhood, and under Morro do Corcovado, respectively.
The pleasant surprise of leaving the dark gallery of the Rebouças Tunnel to the view of the Lagoa Rodrigo de Freitas is truly a unique sensation for those traveling from the Zona Norte to the Zona Sul. Ease and comfort were the advantages gained from the investment of boring through a thick massif full of lithological and structural heterogeneities in its rocks to build this tunnel, which for decades held the title of the longest in the city.
The expansion into Barra da Tijuca through the Zona Sul had to contend with the rugged terrain of the Zona Sul, creating a sequence of tunnels that, until a certain point in history, was seen as impossible to build: the tunnels of the Lagoa-Barra complex, Zuzu Angel (1971), Joá (1971), São Conrado (1971), and the PUC acoustic tunnel (1982).
Returning to Zona Norte to make certain short connections easier, the Martim de Sá Tunnel (Frei Caneca Tunnel) was inaugurated in 1977, and the Noel Rosa Tunnel, crossing the Serra do Engenho Novo, was built in 1978.
Approaching the end of the 20th century, the construction of the Linha Amarela required the drilling of a series of buttresses on the northern portion of the Maciço da Tijuca, inaugurated in 1997: Túnel da Covanca, Túnel falso da Suíça Carioca, Túnel Geólogo Enzo Totis, and Túnel Engenheiro Enaldo Cravo Peixoto. And finally, more recently, the Túneis da Grota Funda were drilled, putting an end to the interruption of the climb up the Serra de Guaratiba and connecting Avenida das Américas and the Túnel da Transolímpica, cutting through the Serra do Valqueire.
Image description: This is a photograph of a road with a tunnel in view. On the left side, there is a hill covered with green vegetation and trees. The road has two traffic lanes, and a car is stopped facing the camera. On the right, there is a concrete barrier and more vegetation. The sky is blue with some white clouds.Covanca Tunnel, entrance from the Água Santa neighborhood
Image description: This is an aerial photograph of a mountainous area. From left to right, we see extensive coverage of dense vegetation, with varying shades of green. In the center, there is a road that cuts through the landscape, standing out for its light color in contrast to the green. As we move toward the background, we observe a more open plain, where some buildings and green areas are located. On the horizon, we see a line of water separating the land from the distance, with a few scattered clouds in the light blue sky.Grota Funda Tunnel
Over the years, the technique of cuts and excavations was improved, with the construction of modern tunnels and the implementation of new technologies to ensure the safety and stability of the excavations. The process of cutting through the hills, therefore, is one of the most striking facets of Rio de Janeiro's urban transformation, reflecting the tensions between the preservation of geological heritage and the need for the city's modernization and expansion
Image description: This is a photograph of a road tunnel. On the left side, we see a stone wall with green vegetation. Moving toward the center, we see a road with two traffic lanes, separated by a white line. On the horizon, there is a landscape with green vegetation and some trees. On the right, there is also a stone wall with green vegetation. The tunnel ceiling is made of curved metal structure. The sky is covered with gray clouds.Geólogo Enzo Totis Tunnel on the Linha Amarela, part of the sequence of tunnels that cut through the northwest slope of the Maciço da Tijuca.
Image description: This is a photograph of an urban road with moving traffic. On the left, there are trees with dense green foliage, including palm trees. In the central part of the image, there is a tunnel with green lights inside it. On the right, there are tall residential buildings with yellow and green façades. In the foreground, there are moving vehicles, including cars and a white truck. On the right, there is also a traffic sign with a no-parking symbol.Entrance to the André Rebouças Tunnel, from Lagoa to Zona Norte
Image description: This is a photograph of a city with modern residential buildings. On the left side, there is a green area with trees and a stone wall. In front, there is a road with traffic lanes and a few moving cars. On the right, there are tall buildings with balconies and windows. In the background, there are more buildings and a hill covered in vegetation. The sky is partly cloudy, with blue and white tones.Cantagalo Cut, a cut between the Cabritos and Cantagalo Hills, connecting Lagoa to Copacabana.
Image description: This is a photograph of a road cutting through a lush green valley, with a large, imposing rock formation in the background. On the left, there are dense trees and a strip of land with some buildings scattered across the hillsides. On the right, more trees and an area where a few vehicles and motorcycles are parked. In the center, the road curves slightly, with two traffic lanes on each side and a car approaching the camera. In the distance, a row of colorful houses is built on the hillsides, creating a vibrant contrast against the gray rock. The sky is covered in clouds, giving the scene a soft gray tone.Everything happens on the roads of Rio de Janeiro, at the entrance to the Zuzu Angel Tunnel in São Conrado/Rocinha, with a bus crossing the lane in a radical maneuver.
Image description: This is a photograph of a road alongside the sea. On the left side, we see an elevated bridge with metal and concrete structures. The road below has two traffic lanes and a central median. On the right, there is a protective wall with metal railings. The sea is calm, with gentle waves breaking against the rocks along the coast. On the horizon, we see a distant island and a pyramid-shaped mountain, known as Morro da Urca, in Rio de Janeiro. The sky is covered with gray clouds, giving the scene a somber tone.Elevado do Joá, one of the boldest engineering works in Rio de Janeiro, built into the rock face of the Pedra da Gávea over the sea
Image description: This is a photograph of a natural setting with urban elements. On the left side, there is a modern bridge with suspended metal structures over a green river. In the background, there is a mountain covered with dense vegetation. In the central part of the image, there is a tunnel hidden in the mountain's rocks. The landscape is dominated by tones of green and gray, with a grayish sky.The subway is undoubtedly responsible for the largest excavations in the Rio hillsides. In this case, the open-air exit of Line 4 to Jardim Oceânico station. Tunnel through Morro Focinho do Cavalo, in Itanhangá. Mind the gap between the platform and the train.
