This is the Siloam Inscription: an inscription found in the historic Hezekiah Tunnel, dating back 2,800 years, which tells how the water channel used in the time of King Hezekiah to provide water to the inhabitants of Jerusalem was dug.
Although it is very common to find writings on public works in Egypt or Mesopotamia, it is a real find to find it in Jerusalem. Thanks to this work, the city was able to supply itself and accumulate water at times when access to it was difficult.
The City of Jerusalem is naturally protected by mountains and natural obstacles. But the fresh water was in a lower area, which put its inhabitants in a situation of danger before a siege.
King Hezekiah feared that the city would be attacked by the other peoples, and by the Assyrians in particular. For this reason, he ordered the construction of the Canal de Hezequías or Canal de Siloé that poured its waters into a cistern protected by the city walls.