The Hexagon

Built in 1923 as the Machines and Tools (Mechanization) Pavilion of the Machine-Building Section at the First All-Russian Agricultural and Handicraft Industries Exhibition, the building designed by Ivan Zholtovsky was subsequently used as the main canteen for the Park of Culture and Leisure (aka Gorky Park), when it was given its Hexagon name. Later the building was repurposed for lemonade production, as a discotheque, and for other uses before being abandoned. In 1999, Moscow City Government declared The Hexagon a listed building.

The Garage Museum of Contemporary Art was founded in 2008 at the Bakhmetievsky Bus Garage, designed by Konstantin Melnikov, and then moved to Gorky Park in 2015, into the previously derelict Vremena Goda (Seasons of the Year) restaurant from the 1960s, which was renovated by OMA – Office for Metropolitan Architecture. Garage is located just steps from The Hexagon, which will comprise the third large-scale adaptive reuse project for the institution and serve to "expand and clarify its architectural program," according to museum director Anton Belov. 

Before hearing from SANAA on the design, here is a short video visualizing The Hexagon's eventual transformation:

And in this short film, Sejima and Nishizawa speak from their Tokyo office about their approach to reviving The Hexagon (be sure to turn on captions for English subtitles):