A science experiment centuries ahead of its time.
See how Eratosthenes, head of the library of Alexandria back in the BC days, calculated with precision the circumference of the planet using the sun and a stick —
Or, if you’re not interested in that kind of thinking, you could just have blind faith, believe that we live on a flat world, worship questionable literature i.e. theological soap operas (The Young And The Restless of the olden days), and by worship we mean ‘go by the book’ on every aspect of those teachings, and generally use your brain for arguing over what clothes to wear, when and how to have sex, what food to eat on which days, and other such groundbreaking aspects of life.
From the bays of a tempestuous Pearl Coast,
Fish a ton of oysters, strike a shiny pearl.