Tucked behind tall hedges on Montmartre's slopes, Clos Montmartre is Paris's oldest working vineyard, a secret garden of 27 grape varieties that produces just 1,000 bottles a year. Peer through the gate on Rue des Saules or catch the view from the Musée de Montmartre gardens: rows of vines that have survived since 1933, tended by city gardeners who keep this improbable winemaking tradition alive.