1 2 3 The Auditorium Oscar Niemeyer in Ravello, southern Italy is an iconic new concrete building perched above the Amalfi coast. The €16·7 million, 400-seat venue was completed in 2010 and provides a much-needed venue for this world heritage site's wealth of renaissance-inspired art and cultural events. The main structural feature is a 35 m vaulted roof supported on a slab cantilevering 12 m out from supporting walls, giving the building the appearance of floating in air. This paper reports on the many multi-disciplinary design and construction challenges involved in delivering this unique and geometrically complex building on a steep and confined site. A key issue was the need to respect the architectural vision while achieving an efficient and sustainable design.