I know this is just a meme, but I’ll share something I recently learned since I find it fascinating.

The oceans started out as freshwater! Water evaporated from them, rained down as freshwater and formed into rivers and streams, and the process of flowing picked up trace amounts of salt from the ground and riverbeds. These rivers eventually dumped their ever-so-slightly salty water into the ocean. Then, the tiny tiny tiny bit salty ocean evaporated some pure water out, leaving less water - meaning the remaining water just got a little bit saltier in comparison. This process repeated for millions of years and those tiny increments resulted in the very salty oceans we have now.