It is "upside down" because the merchants in the play were on a pilgrimage from Venice to Belmont, the home of the queenly princess, Portia, whose assistant was Nerissa. Shakespeare asserts that one can get from Venice to Belmont either by land or by sea. It turns out Belmonte is an inland town in northeastern Portugal which fits that geography. Furthermore, today's Belmonte is the home of some 300 Jews (among its population of 3,000) who have lived there since the 16 century as "Christians," but in the 1980s they "came out" publicly as Jews. Although no secret to the Gentiles, they literally had worshiped their Jewish God underground, while also dutifully attending church and silently telling God that place was nothing but a pile of stones. Such were the consequences of the Spanish and Portuguese Inquisitions (Shakespeare probably anglicized Belmont, dropping the "e").