> Normally, water that has accrued in a drainage basin eventually flows out through rivers or streams on the Earth's surface or by underground diffusion through

> Normally, water that has accrued in a drainage basin eventually flows out through rivers or streams on the Earth's surface or by underground diffusion through permeable rock, ultimately ending up in the oceans. However, in an endorheic basin, rain (or other precipitation) that falls within it does not flow out but may only leave the drainage system by evaporation and seepage. The bottom of such a basin is typically occupied by a salt lake or salt pan. https://en.wikipedia.org/wiki/Endorheic_basin https://en.wikipedia.org/wiki/Endorheic_basin It turns out that they are salty. They are often not as salty as the ocean though because oceans have been getting saltier for millions of years.