You have to pay attention to History,Think Pre-Man!Regardless of what you hear from The many Authorities of Govt,Health,etc.,Take a Good look at the soil in your Location,Have you found Seashells?Yes? Why? I'm on a 500 ft hill,Above the rest of the city,what the hay?This soil came from somewhere else,Right? Wrong! There are seashells on top of Mount Baldy,in fact there are seashells on top of All Our Mountain Ranges,Why? Because the Ocean was there!Fact: L.A. Basin is just that,A Basin,Such as:Water in,Water out,Water in,Water out,etc.!Who is The Authority to say,That isn't going to happen Again?Just because humans are here,doesn't Mean Jack!That said,Make the best of it!