[labster]

Lighthouses fulfill roughly the same purpose as hazard signs on freeways — everyone makes more money when ordered goods actually arrive. Rocks on the sea are more dangerous than falling rocks on the roads.

Monument lighthouses have an extra purpose: they project power and wealth. Merchants know this place is Important. Like modern day monuments, whether people need a giant expensive building/statue/obelisk to learn this or it’s just a vanity project for the ruler is a matter of opinion. People aren’t really all that different over the last 2000 years.