Lyon's silk weaving history is built into the city itself. Its famous traboules created a complex network of covered, often hidden, passageways which linked courtyards and staircases, provided quick routes to the river, and enabled manufacturers to transport their wares safely and out of the rain. There were at one time as many as four hundred traboules, but now only forty or so are open to the public, a fascinating glimpse of old Lyon. There is also an excellent silk museum.