This complex is located where a stream ran, one of the three that carried water from the highlands of the city to the Río de la Plata. These currents were called the Terceros and this one in particular, El Tercero del Sur, was known as El Zanjón de Granados.
Under the a historic building from the 19th century, a section of the stream bed was found with remains of foundations, walls, floors, cisterns and cesspools built and destroyed between 1730 and 1865.
In 1985 the river it was tubed and those underground tunnels can now be visited.
During the tour you learn about 4 centuries of life in Buenos Aires. Containers, utensils and remains of constructions from 1700, 1740 and 1830, cisterns, cisterns and a drainage system are exhibited.