Madagascar: For a sailor on a ship in the 17th century, there weren’t many options for getting or receiving messages from other ships or back home. But sailors for the Dutch East India Company used a rudimentary postal system for ships: a series of inscriptions on stones at a beach on tiny Nosy Mangabe Island, under which seamen could leave letters for another ship to pick up and deliver. Experts recently documented these inscriptions and found 40 of them, left by at least 11 different ships.