Italian architecture practice Studio Fuksas have completed the largest new building in Rome in over 50 years: a convention hall and hotel nicknamed The Cloud.

Opening this month after nearly two decades in development, the New Rome/EUR Convention Hall will host exhibitions and conferences expected to bring in as much as €400m (US$437m, £358m) annually to the city of Rome.

Located south of the city’s core, the complex is open to the public and is flanked by two new public squares for leisure and outdoor activities.

Studio Fuksas are known for their abstract shapemaking –their nearly-completed theatre in Tbilisi, Georgia, is a case in point – and this is demonstrated in the convention hall by the inclusion of a cocoon-like building within a building – the eponymous ‘cloud’.

Built using 15,000sq m (161,500sq ft) of advanced membrane fibreglass and flame-retardant silicone levels, supported by escalators and walkways, the interior structure has five levels and leads to a 1,800 capacity auditorium. It is accessible via the ‘Forum’ – an artery walkway that fuses it together with the main building’s outer shell.

The final architectural concept is the ‘Blade’ – an autonomous building split into 17 floors and containing a new 439-room hotel. Spread over 18,000sq m (193,750sq ft), it will also include seven boutique suites, a spa and a restaurant.

The complex has been constructed from 37,000 tons of steel – equivalent to four and a half Eiffel Towers. Over 58,000m of glass has also been used; enough to cover the surface of 10 football pitches.

Integrated air-conditioning, rainwater harvesting, a natural ventilation system and solar panels have been added to make the buildings eco-friendly as possible. It is also designed to be earthquake-proof.

An official inauguration ceremony will take place on 29 October.