Often enough, straits imply a political canalization and thus become an instrument of identification and selection, which itself has a long history. After the initial euphoria of the age of discovery, passengers leaving for the New World from Spanish ports of call had to go through precise identification practices as early as the mid-16^th century, practices that their European descendants renewed in the 20^th century when they were gathered at entry-points like Ellis Island.

Thus, since the early modern period, the more geographical mobility has become available, the more its political implications have become evident. Suez and Panama not only stand for further achievements on the way to unimpeded world-wide circulation, they have also become markers of strict regulation. These narrows —zones of passage and transit spaces that simultaneously circumscribe and restrict exchange— ought to be part of our attention now even more than ever, as they are the place where the actual mechanisms of globalization become visible.