Far below the southern perimeter of the Parc des Buttes-Chaumont runs one of the curiosities of the Paris Métro – line 7bis. A short, self-contained spur from line 7 leads northeast from Louis Blanc and loops through some of the quieter residential neighbourhoods of the 19ème. Trains and stations are lightly used and it’s possible to enjoy the rare sensation of occupying a deserted métro platform. At Buttes-Chaumont the two platforms are in adjacent tunnels - large round arches have been pierced between them allowing each platform to be viewed from its opposite number. The sepulchral quality is unmistakeable. White tiles with bevel edges arching overhead enclose a consecrated space and a devotional air prevails as we examine the enigmatic arrangements of artefacts visible through the Romanesque archways.