Mexico established a guano mining colony in the Pacific, then forgot about it, leading to a full-scale fly lord situation
Clipperton is a small island off the west coast of Mexico (which is a large country off the east coast of Clipperton). Almost everyone ignored him until the late 1900s when they realized he had a very valuable property: he was covered in shit. Millennia of compacted seabird droppings were worth a fortune as fertilizer, and a three-way diplomatic showdown ensued between Mexico, the United States, and France, all seeking to claim the island and to become the world’s leading power pooper. Mexico eventually won, and by 1910 the island was home to a small, bustling community of guano miners. Unfortunately, that was the year the civil war broke out in Mexico. Unwilling to let the Mexicans have their fun, the rest of the world soon plunged headlong into World War I. In all the chaos, everyone just somehow forgot Clipperton.
Since TikTok had not been invented, the people of Clipperton had no way of learning about world events. They just knew that their regular supply ship didn’t show up for a month. And then the next one didn’t show up either. A passing American ship offered to bring the islanders to safety, but the the offer was refused by the colony commander, Captain Raymond Arnaud, who feared a ruse to seize the disputed territory. The other islanders voted to stay with Arnaud, determined to do their duty and stay put until help arrives from the mainland. It was a horrible mistake.