Our Lady of Conception Fortress, built between 1713 and 1718, was a strategic point for the conservation and defense of Rio de Janeiro during the colonial era. It came to being due to the necessity of placing cannons in a high enough location to protect the shore of the old Cais do Porto wharf and nearby islands. Five years after its inauguration, the Fortress already held the third largest artillery stockpile in Rio de Janeiro.
The Fortress has been declared a heritage site by the Institute of National Historic and Artistic Patrimony (IPHAN) since 1938 and today houses the Army’s 5th Surveying Division, a Military Organization under the Directory of Geographic Services (DSG). It stores cartographical documents and aerial films of the country. With a view of Rio’s bay, the space preserves a chapel and the dungeons where political prisoners, such as those from the 18th-century Brazilian separatist group ‘Inconfidência Mineira,’ were held.