La Quercia Rossa del Trotter

This oak grows on a horse-racing track that stopped racing a century ago and became a school instead. Parco Trotter takes its name from the Società del Trotter, which ran harness races here from the 1800s until the track moved to San Siro in 1924; when the sporting company folded, Milan's city council bought the abandoned oval and turned it, starting in 1919, into Casa del Sole, a 128,000 square metre open-air school for children with tuberculosis and other chronic illness, built on the belief that fresh air and space were themselves a treatment. The ring shape of the old racetrack still defines the park's paths today, cut across by a single straight avenue of plane trees. This red oak, planted not long after the school opened, now stands about 40 metres tall, taller than any other tree on this list, with a trunk 4.3 metres around, growing beside Via Giacosa near the park's old chapel. The school never fully closed. Children still attend classes on these grounds, which is why the park keeps unusual hours, open to the public only outside school time, free every day it opens rather than at any point in between.