The “Arches of Lapa”, as the famous Lapa Acqueduct in Rio de Janeiro is known, are celebrating their 80th anniversary as an officially-listed Brazilian Cultural Heritage Site last April 5th. Declared a protected site by the Institute of National Historical and Artistic Heritage (Iphan) in 1938, the site, also known as the Carioca Aqueduct, is one of Brazil’s most notable architecture works and one of the city’s most well-known sights.
The Aqueduct, considered the largest construction work undertaken in Brazil during the colonial period, was built in mortared stone and consists of 42 double arches, each 17 metres high, that extend for 270 metres. The full architectural ensemble includes the arches themselves, the public promenade under 
them, the National School of Music and the Church of Our Lady of Lapa. The area is also famous for the various cultural and gastronomic attractions of Lapa, Rio’s most famous Bohemian quarter.
When it was built in the 18th century, the aqueduct served both as a way to bring water from the springs of the Carioca river into the city and as a crossing path between the Santa Teresa and Santo Antônio hills. Later on, they became an overpass for the trams that circulate through Rio’s Santa Teresa neighbourhood. The structure was inspired by Roman arches and by the Águas Livres aqueduct in Lisbon.
Source: www.brazilgovnews.gov.br