Giardino della Biodiversità

The University of Padua founded its botanical garden in 1545 as the "Horto Medicinale", a garden of medicinal plants for teaching medicine. Still on its original site and true to its Renaissance plan — a square set within a circle — it was added to the UNESCO World Heritage List in 1997 as the oldest university botanical garden still in its first location.

In the early 2010s the university decided to extend onto adjoining land so that it could pursue its scientific and educational mission without overloading the historic core. The commission went to architect Giorgio Strappazzon of VS Associati, on a tight schedule: the building had to be ready for the 2015 Milan Expo, with which it was linked. Construction took about three years and kept to the announced budget of around €20 million.

The Giardino della Biodiversità was inaugurated on 15 September 2014 in the presence of Rector Giuseppe Zaccaria, Mayor Massimo Bitonci and the architect. The area given over to plants grew from about 22,000 to 37,000 square metres. Visiting the site, Renzo Piano called the building "a true miracle".

The complex reads as a single glazed wall 100 metres long and 18 metres high, behind which five greenhouses are lined up. The architect described it as a great leaf that breathes, opening and closing to regulate its temperature. The glass, supplied by Veneto Vetro, is held by small Fischer point fixings with no external profiles or through-holes, giving the façade an unbroken surface.

The building aims for self-sufficiency in water and energy: its form and materials make the most of solar gain, rainwater is harvested, and concealed sensors continuously monitor humidity, light and air quality. The opaque panels carry a photocatalytic coating intended to clean the surrounding air. The greenhouses are arranged as an ideal section of the globe from the equator towards the poles, moving from hot, very humid conditions to progressively drier ones.

Some 1,300 species are spread across five biomes: tropical rainforest, sub-humid tropical forest, temperate, Mediterranean and arid. Among the plants on show are useful species such as mango, banana, cacao and coffee, tropical aquatic plants, and rarities including Franklinia alatamaha, extinct in the wild, and Welwitschia mirabilis from Namibia.

The route follows three themes — the plant and its environment, the plant and people, and the plant in space, the last dealing with extreme conditions and the impact of human activity. Panels, interactive installations by the Dotdotdot studio and documentaries accompany the displays.

The Giardino della Biodiversità extends the historic Orto Botanico, a short walk from the Basilica of Saint Anthony. Visitors usually take in the Renaissance garden first, with its beds of medicinal plants and the so-called Goethe palm, planted in 1585 and sheltered in an octagonal glasshouse, before moving on to the contemporary greenhouses, where the scientific interpretation is fuller.

Two to three hours allow an unhurried look at both parts, and the pairing of 21st-century glass with a 16th-century plan is one of the site's great pleasures.