If you’re a Cincinnati native, the name “Symmes” should be very familiar to you.   That name adorns streets, townships, and businesses around greater Cincinnati as a relic of the man who originally owned the entire town: John Cleves Symmes, a colonial-era real estate mogul who owned and sold off a giant tract of land in Southwest Ohio called the “Symmes Purchase”.  It’s always interesting to hear how an entire city, it suburbs, probably around a million people today, was built from a single plot of land owned by one person.  An even more interesting story is that of his nephew and namesake, who dedicated his life to developing and popularizing a highly detailed theory of a hollow earth.  Between them, the two John Cleves Symmes had one of the most interesting careers in real estate of any family in history.