By comparison, my longest unbroken vertical is a complete 22 vintage, 24 year vertical of Vesuvio from 1989 to 2012. Must be time for another Vesuvio vertical tasting soon...
My second longest is Dow - 7 vintages from 1955 to 1972 (1955, 1958, 1960, 1963, 1966, 1970, 1972) and then 6 from 1977 to 1994 (1977, 1980, 1983, 1985, 1991, 1994). If I bought a Dow 1975 I would have a 14 vintage vertical.

What verticals do other people have in their cellars?