El The Historical passage 5 de mayo was discovered in the year 2011 when work was being carried out for the construction of the depressed crossing on 5 de mayo boulevard and a part of the vault was accidentally fractured and confused with the an old drainage system. In 2012 began with the research project and the rescue of the bóveda. A fracture can be seen in the upper part of the vault, which was made to the structure to enter the tunnel for the first time, this is where the rescue project begins, which was done by hand, without any machine, only with picks, shovels and buckets.