Agulhas Negras Peak

Agulhas Negras Peak (Pico das Agulhas Negras,, lit. 'Black Needles Peak') is the fifth-highest mountain in Brazil, standing at 2791 m above sea level, making it one of the highest in the Brazilian Highlands. It is located in Itatiaia National Park, in the Mantiqueira range, on the border of the states of Rio de Janeiro and Minas Gerais. It is the highest point in the state of Rio de Janeiro, the third-highest in Minas Gerais, and the second-highest in the Mantiqueira range.

The climb to the top of the mountain was first attempted by Franklin Massena in the year 1856. Further attempts were made by André Rebouças in 1878 and by Horácio de Carvalho in 1898, but the summit was only reached by Carlos Spierling and Osvaldo Leal in 1919.

Etymology
Its name means Black Needles Peak, because of the sharp dark rocks on its top, which give it a distinctive shape. The peak's massif is known as Itatiaia, which means "stone with many sharp points" in the Tupi language. The highest rock, with the summit, is known as Itatiaiaçu, or simply Açu (a Tupi suffix meaning "big") among Brazilian mountaineers.

Geography
Agulhas Negras Peak can be seen to the northwest of Resende when driving between São Paulo and Rio de Janeiro on the Via Dutra highway, but this is only possible at a few points on the road, because a lower mountain range closer to the road stands in the line-of-sight at most other nearby spots.

A mountain shelter called Abrigo Rebouças is located near the base of the peak, at an elevation of about 2350 m. It is accessible by a gravel road (BR-485) from the BR-354 federal highway at the Garganta do Registro mountain pass, via Itatiaia National Park's north entrance. The access road reaches an altitude of 2460 m at the entrance of the park, and a short spur from it leading to a communications tower of the Eletrobras Furnas electricity company reaches 2662 m; these are the highest points one can reach in a regular car (as opposed to off-road vehicles) in Brazil.

Elevation measurements
For years, Agulhas Negras was thought to be the highest mountain in Brazil. The title later went to Pico da Bandeira, in the Caparaó range between the states of Minas Gerais and Espírito Santo (now known to be at 2891 m). In 1965, it was found that Pico da Neblina, in the state of Amazonas, was, in fact, the highest, with a currently revised height of 2995 m.

Even then, Agulhas Negras was still thought to be the highest point in the Mantiqueira range, until a 2001 GPS measurement (later confirmed by an official joint expedition of the Brazilian Army and the Brazilian Institute for Geography and Statistics - IBGE) showed that nearby Pedra da Mina was that mountain range's highest point at 2798 m, about seven metres higher than Agulhas Negras. Pedra da Mina was higher even though Agulhas Negras was also found to be slightly higher than previously thought, at 2791.55 m, rather than its previous official altitude of 2787 m. Agulhas Negras remains the highest point in the state of Rio de Janeiro.

In 2015, IBGE completed a new and more accurate mapping of the Brazilian territory regarding the geoid, the irregular imaginary surface based on the Earth's gravitational field that is the reference for altitude measurements. This led the institution to recalculate the altitude of the mountains measured in the earlier project, according to the new reference. The new data were published in February 2016. Agulhas Negras was then found to stand at 2790.94 m, a difference of 61 cm or about two feet.