This historic building, rising above the ill-kept neighbourhood of São Cristóvão in Rio de Janeiro’s marginalised North Zone, houses a research institute and museum dedicated to the study of the skies known as the Museum of Astronomy and Related Sciences or Museu de Astronomia e Ciencias Afins (MAST).

The building was built between 1913-1921, originally as a new home for the National Observatory that had up until then been situated on the infamous Castelo Hill (Morro do Castelo), demolished in 1921 as part of an urban reform.

As a museum, it includes a permanent exhibition with interactive experiments in the basement, countless scientific instruments, a scaled model of the Solar System, and even a large chunk of asteroid on display in the courtyard.

However its best-known and most beloved regular activity occurs every Saturday night when MAST’s telescopes, some over a century-old, as well as some modern models are made available for the public to use in the building’s dome.

The museum is located in São Cristóvão which is not a particularly tourist-y area, and according to some reports can get a bit rough, especially after dark. Take reasonable precautions if visiting the museum after dark.