What does the red mean?

[v0031]

Early sections of San Francisco were built out of ships abandoned by prospectors.
The Gold Rush conjures up images of thousands of “’49ers” heading west in wagons to strike it rich in California, but many of the first prospectors actually arrived by ship—and few of them had a return ticket. Within months, San Francisco’s port was teeming with boats that had been abandoned after their passengers—and crew—headed inland to hunt for gold. As the formerly tiny town began to boom, demand for lumber increased dramatically, and the ships were dismantled and sold as construction material. Hundreds of houses, banks, saloons, hotels, jails and other structures were built out of the abandoned ships, while others were used as landfill for lots near the waters edge. Today, more than 150 years after the Gold Rush began, archeologists and preservations continue to find relics, sometimes even entire ships, beneath the streets of the City by the Bay.

[Meclazine for Israel]

Images in this context are like imagined thoughts.