Mdina's ditch was an important element of its fortifications. It was first created in the 15th century, but was rebuilt by the Knights of St John's military architect Charles François de Mondion. More recently, the Mdina city walls had become overgrown with ivy and vegetation; the ditch was filled by 273 citrus and seven olive trees.
In a regeneration project completed in 2015, the trees were removed or moved, and the bastions restored. The citrus grove was replaced by a mix of lawn, stone paving, and saplings in pots. The landscaping has proved controversial, with an outcry over the removal of the mature citrus trees, the lack of shade, and the stark aesthetic. However, the restored bastions now gleam splendidly and are much more visible, and the gardens are far more accessible. The ditch now forms a space for festivals such as food fairs and concerts. Enquire at the tourist office about forthcoming events. The most common access is via stairs at the southwest corner of the walls near the San Pietro Bastion.