def url(quad):
    """ creates the url for a given quadkey. """
    key = 'AuZ2rzQL4BFpZbThyMutLjCSwreiFEPg66lx4ZTsbWIP2fvhEupamMwphvkb82sb'
    root = 'http://ecn.t3.tiles.virtualearth.net/tiles'
    return '{}/a{}.jpeg?g=195&mkt=en-US&key={}'.format(root, quad, key)