A giant pit of a million plastic balls has taken over the National Building Museum in Washington DC, creating a synthetic seaside inside the 19th-century building’s Great Hall.

The Beach, designed by New York-based practice Snarkitecture, spreads across a 10,000 sq ft space in the former US Pension Bureau HQ – conceived by army officer and architect Montgomery C Meigs.

A walled mirror gives the impression of an endless ‘ocean’ while a 50-ft-wide shoreline is sprinkled with beach chairs and parasols to replicate the experience of visiting a real beach. Gallery-goers can plunge into the plastic ‘water’ or lounge around, soaking up the architecture.

‘Although it is bound to be an entertaining retreat from the summer heat for our visitors, it also turns our understanding of the natural environment on its head and offers us the opportunity to question our own expectations of the built environment,’ says Chase Rynd, executive director of the National Building Museum.

The installation’s stark white palette makes it stand apart from its palatial setting in the National Building Museum’s Great Hall, which takes inspiration from Michelangelo’s renaissance architecture.

Snarkitecture co-founder Alex Mustonen says the firm wanted to ‘create an architectural installation that reimagines the qualities and possibilities of material; encourages exploration and interaction with one’s surroundings; and offers an unexpected and memorable landscape for visitors to relax and socialize within.’

He adds: ‘Snarkitecture distinguishes itself by operating in the territory between art and architecture, emphasising the transformation of the familiar into the extraordinary and the National Building Museum has been a devoted supporter of our aspirations.’

Snarkitecture’s The Beach – on show until 7 September – follows last summer’s similarly immersive BIG Maze installation by the Bjarke Ingels Group.