[mikro2nd]

From their website (https://iho.int/): "IHO works to ensure that all the world's seas, oceans and navigable waters are surveyed and charted, thereby supporting safety of navigation and the protection of the marine environment. It coordinates the activities of national hydrographic offices and sets standards in order to promote uniformity in nautical charts and documents. It issues survey best practices and provides guidelines to maximize the use of hydrographic information."

Lest you think this merely a paper-shuffling exercise, if there's a shipping accident, a huge amount of legal liability rides on the accuracy and up-to-date information in the charts. What these guys do underpins a huge amount of maritime law and international shipping. Definitely one of the really important, useful international orgs.