The Jardí Botànic Històric (Historic Botanical Garden), a tiny gem among the gardens of Barcelona, nestles in the hollows of two disused quarry pits in the Foixarda sector of Montjuïc, behind the Museu Nacional d’Art de Catalunya (National Art Museum of Catalonia, MNAC). Because it is enclosed by steep slopes and situated on Montjuïc’s shady side, cold air accumulates at its lowest levels. As a result, temperatures can be up to four degrees colder at the bottom than in the upper areas of the garden. This favours the growth of Euro-Siberian plant species typical of colder climates.