Russian director Ilya Khrzhanovsky's long-mythologised film project DAU is finally arriving at the Venice Film Festival, two decades after he began building a sealed, fully functioning recreation of a Soviet research institute in Kharkiv, Ukraine. What started in 2006 as a conventional biopic of Nobel Prize-winning physicist Lev Landau, nicknamed "Dau", spiralled into an immersive, controversial experiment in which thousands of participants lived under authentic period conditions for years, generating multiple spin-off films, art installations and persistent allegations of abuse and exploitation.

Participants reportedly wore only 1930s-60s clothing, ate Soviet-style food and were cut off from modern technology, while some former KGB officers played their real-life roles and could detain fellow cast members. Around 700 hours of 35mm footage and 8,000 hours of dialogue were recorded, including a 2011 scene in which the set was set alight by real neo-Nazis, one of whom later died in prison. Khrzhanovsky kept his original biopic footage, shot between 2008 and 2011, in storage for over a decade before finishing the 165-minute "mother film", titled simply DAU, which premieres in competition at Venice this month amid renewed controversy over its Russian origins.