The bridge

In the last century, Stefan Batarmeth, the person in charge of listed monuments, sought to understand the nature of the damage to many of the arches under the bridges over the Tagus. He very soon noticed the role played by the over-tall masts of the fishermen’s boats, which were tight for space on the river and dreaming only of voyaging on the open sea.
As a protective measure, and also out of respect for the fishermen, Batarmeth set about designing a boat with shorter sails capable of both river and sea navigation. By chance, he discovered that the marks left by the masts scraping under the arch of each of the damaged bridges invariably formed a drawing, or rather a plan, more or less representing the shape of a vessel. Seeing this as a gift from heaven, Batarmeth used these plans to produce his ideal boat and personally tried out his creation.
After an uneventful journey on the river, hardly had Batarmeth reached the sea than he sank. Just before going down, he made one last upward glance to see if some damage had not just suddenly appeared in the celestial arch.