The Horse Chestnut of the Cordonata

A Balkan mountain tree has no business being this large on a Roman hill. Aesculus hippocastanum grows wild in a handful of ravines in the mountains of northern Greece, Albania and North Macedonia, where the summers are cool and the soil stays damp; western Europe only met it in the 1500s, through Constantinople, and planted it everywhere as an avenue tree. Rome is close to the edge of what it tolerates, which is why the city has exactly one on its monumental register and why a trunk 3.45 metres around here counts for more than the same figure would in Vienna. It stands on Via delle Tre Pile, the ramp cars take up the Capitoline, on the right-hand side of Michelangelo's Cordonata as you climb. Roma Capitale registered it for size and for landscape value, meaning the view it belongs to rather than the tree alone. Almost everyone who photographs the staircase stands in its shade to do it. Fifty metres away on the other flank of the same climb grows the ombu from Argentina, so the two flanks of Rome's most famous stair are held by a Balkan mountain tree and a South American pampas tree, and neither is Roman at all.